Perspectives on human development across the life span A Student Journal
In this issue:
Volume 2, Number 1
Unit Two: Prenatal Development
A Journal of Developmental Psychology to support Psychology 30, a course offering of Saskatchewan Education
In this issue: From conception to birth Volume 2, Number 1 Feature Articles Looking through the eyes of the fetus…..What do you see?
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This article describes the developmental process from conception to birth. In this article, the physical, mental and emotional development of the fetus is described.
Cloning: A Twist on Creation
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Scientists are on the brink of finding ways to cure some of our nastiest diseases, but their research, though fascinating, is highly controversial.
A Double-Edged Sword
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Scientific developments often present society with new moral dilemmas, perhaps never more so than with the encoding of the human genome.
Labour and Delivery
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This article describes the process of labour and delivery, the culmination of 38 weeks of phenomenal growth and development, the emergence of a brand new member of the human race!
Looking through the eyes of the system of supports….What do you see?
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This article describes the various support systems that work together to support and nurture healthy prenatal development. Using Bronfenbrenner's Ecological Model (1979), this article will describe how each of the various levels of supports work to nurture and promote healthy prenatal development.
Influences on healthy prenatal development
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While the developing child is relatively insulated from the outside world while in the womb, still, there remain many possible factors and agents that can seriously, and often negatively, influence development. This article describes the wide range of substances and conditions, called teratogens, which influence prenatal development.
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Unit Two: Prenatal Development
A Journal of Developmental Psychology to support Psychology 30, a course offering of Saskatchewan Education
Life span development approach: From conception to birth
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This article considers how the life span approach to development can be used as a conceptual organizer to describe the developmental process from conception to birth.
Making connections …. My Anthology
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To truly make Ages and Stages your own, we provide a space where you can keep sayings, pictures, poems, anecdotes, musical lyrics, anything that you find intriguing, inspiring, amusing or thought provoking.
From both perspectives….
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Cloning of human organs for transplant should be allowed.
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Unit Two: Prenatal Development
Looking through the eyes of the fetus…..What do you see? This article describes the developmental process from conception to birth. In this article, the physical, mental and emotional development of the unborn child is described.
At no other time across the life span, does the human body experience the same rate of growth as it does from conception to birth. In just 40 weeks, beginning from the moment of conception when but 1 of the 20,000 spermatazoa necessary to chemically break down the outer layer of the ovum achieves chemical union with the female egg, to the point of labour and delivery, a human baby with all of the fundamental capabilities and potentials is created. This miracle of creation is known as the prenatal stage of development. The prenatal development of a human being occurs in three stages. The germinal period of development is the first two weeks of development, characterized by rapid cell division, the beginning of cell differentiation, and implantation of the blastocyst into the uterine wall. By approximately 1 week after conception, the zygote is composed of 100 to 150 cells. The differentiation of cells commences and the zygote becomes differentiated into three layers: The blastocyst is the inner layer of cells that later develop into the embryo; the trophoblast is the outer layers of cells that later provides nutrition and support for the embryo. Implantation of the zygote into the uterine wall takes place about 10 days after conception. (Santrock, 1999) The embryonic period is the period of pre-natal development that occurs from 2 to 8 weeks after conception. The embryo's endoderm, the inner layer or cells, primarily produces internal body parts such as the respiratory and digestive systems. The middle layer of cells, called the mesoderm,
will become the circulatory system, bones, muscle, excretory system and reproductive system. The outer layer of cells, the ectoderm will become the nervous system, the sensory receptors (eyes, nose, ears) and skin. As the embryo develops so too does the placenta, the umbilical cord and the amnion (fluid filled sac). (Santrock, 1999) The fetal period is the period of development that begins 2 months after conception and lasts for 7 months, on the average. Three months after conception the fetus is 10 centimetres long and weighs approximately 60 grams. It has become active, moving its arms and legs, opening and closing its mouth, and moving its head. The face, forehead, eyelids, nose and chin are all distinguishable, as are the arms, hands and legs. At four months, a growth spurt occurs in the fetus' lower parts. By the end of the fifth month, toenails and fingernails have formed and the fetus is more active. By the end of the 6th month, the eyes and eyelids have completely formed, a grasping reflex is present and irregular breathing occurs. In the last 2 months, fatty tissues develop and the functioning of various organs such as the heart and kidneys steps up. (Santrock, 1999) During each of the three stages, not only is there biological development occurring at a remarkable pace, but also cognitive and socio-emotional development as well. In terms of the cognitive development of the unborn child, some simple aspects of the functioning of the human nervous system appear Page 4
Unit Two: Prenatal Development very early. Indeed the blood circulation system and the nervous system are the first to function in embryonic life, with heartbeat commencing in the third week following conception. By the second month, an avoidance reaction – the withdrawal of the hand region buy contraction of the neck muscles – occurs if an unpleasant stimulus is applied to the embryonic upper lip. These developments imply that simple reflexes are already established at this stage with the appropriate synaptic connections and interneuronal activity being brought into play in order to coordinate muscular movements. (Rose, 1989, p. 192) The subject of the precise developmental process of the brain and central nervous system is the subject of intense research. The human brain holds about 100 billion nerve cells, or neurons. Each neuron forms contacts with a thousand others, on average, making for a system with at least 100 trillion interconnections. Moreover the system appears to be wired up with almost perfect accuracy. How is this rather impressive feat of engineering accomplished? The basic wiring plan must be encoded in the genes. It is evident from studying the developing embryos of animals that nerve cells are created in or travel to designated regions of the brain, and once in place send out axons along pre-programmed paths to make contact with specific targets. Neurobiologists have recently discovered another basic principle, one that perhaps explains the extraordinary fidelity of the brain's interconnections. The basic wiring plan put into place by genetic instructions becomes modifiable by experience during a critical period in the infant's life. Axons from the retina of the eye grow into the developing brain and make a multitude of connections in the optical cortex. There is then a kind of testing period during which the connections that are used less get pruned away in favor of those that make the system work right. The refinement of the wiring system may be a general principle of the developing brain. It may also be the mechanism that underlies the existence of critical windows of time during which an infant
must learn certain skills, such as the period in the fourth month of life when the infant's brain develops binocular vision. There seem to be other critical periods, less precisely defined, for the development of language and sociability. Children who for some reason fail to acquire these skills during the critical period may never do so. (Wade, 1998, p. 150) It seems somewhat silly to suggest that a developing human fetus, enveloped safely in the mother's womb, swimming in a sea of amniotic fluid and almost perfectly insulated from the outside world, could develop a basic temperament, or personality. But that is the case. Every individual is born with a distinct, genetically based set of psychological tendencies, or dispositions. These tendencies, which together are called temperament, affect and shape virtually every aspect of the person's developing personality. Temperament, and therefore personality, is epigenetic, not merely genetic: it begins in the multitude of genetic instructions that guide the development of the brain and then is affected by the prenatal environment. (Berger, 2000, p. 219) The fetus is no passive passenger in the womb, nor is the woman simply “carrying” the fetus. Development is interactive, even before birth (Kisilevsky & Low, 1998). Beyond the physiological interdependence, fetus and adult have a much more intellectual, brain-based interaction. Beginning at about 9 weeks, the fetus moves its body in response to shifts in the woman’s body position, with imperceptible movements of tiny heels, fists, elbows and buttocks. Soon the woman notices flutters, at first so faint she wonders if gas or imagination, instead of a developing person, is the cause. Such momentary discomfort aside, the perception of fetal movements usually evokes feelings of wonder. Indeed, many parents-to-be, fathers as well as mothers, enjoy rubbing the woman’s rippling belly. The fetus feels and responds to such stimulation, beginning what may become a lifelong pattern of communication by touch
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Unit Two: Prenatal Development (Ronca & Alberts, 1995) Interestingly, a woman’s daily rhythms of running, bending and resting affect fetal movement schedules, and infants who are quite active were often unusually active in the womb. Thus both parties adjust to each other’s particular movement habits before birth. Toward the end of prenatal development, other fetal sensory systems begin to function, and again, interaction between fetus and mother-to-be is apparent. For example, how much amniotic fluid the fetus swallows depends partly on the taste of that fluid: fetuses swallow sweetened fluid more rapidly than noxious fluid, and thus their lungs, digestion and nutrition are intimately related to the particulars of their mother’s diet (Carlson, 1994). But the most remarkable fetal learning involves hearing. Newborns remember certain sounds heard before birth, including voices and speech patterns. Research suggests that, at least in some ways, fetuses prepare more than just their reflexes and organ systems for physiological functioning after birth: they also begin to accustom themselves to the particulars of the social world that they soon will join. Meanwhile, mothers begin to identify features of their future offspring: almost all pregnant women, by the last trimester are talking to, patting, and dreaming about their long-awaited child. (Berger, 2000, p. 106)
Making connections …. • •
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Using a medium of your choice, compose, construct or create a visual metaphor for the nature of prenatal development. Using the table of human development from conception to birth supplied in the Ages and Stages journal, convert the table to an alternate graphics organizer structure such as a poster or timeline. • Finding pictures or diagrams of prenatal development will greatly enhance your poster or timeline. Reflection: An important point about hereditary influences is that there are no genes for behaviour. • What is the significance of this statement? • If there are no genes for behaviour, how is our behaviour determined? Using the statistics about embryonic and fetal weight and length, create a bar graph of prenatal development
And so in summary, during the 40 weeks of prenatal development, all 3 aspects of our Being, physical, mental and emotional, are developed. This is a time of phenomenal development, in fact, at one point in the fetal development stage, 16,000 neurons (brain cells) are being created every minute! In that one simple fact lies the incredible interaction and interdependence of prenatal development. For as the physical development of neurons is taking place, so the cognitive structures of the brain are being built, cognitive structures which may well be the seats for emotions, attitudes, motivations which are the basic building blocks of personality!
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Unit Two: Prenatal Development
Fetus
Developmental Period
Mother
Father
First Trimester 4th Week
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8th Week
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Heart pumping blood Backbone forming Small tail More susceptible to damage from drugs, smoking and alcohol than later in pregnancy Nervous system and digestive tract forming Kidneys begin to produce urine Eyes, arms and legs forming Length - 1 centimeter Weight - 1 gram
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• •
Milk tooth buds forming Face and features forming Arms and legs showing divisions at elbows, ankles, etc. External genitals forming Intestinal tract forms Tail disappears Heart beats 25th day Long bones, internal organs and brain developing Length - 3 centimeters Weight - 4 grams
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No menstrual period Time of adjustment and doubt even if baby was planned Hormonal changes can cause mood swings Extra demands on body cause tiredness and possibly decreased interest in sexual activity Increasing size of uterus causes more frequent urination Slow down of bowel muscle can cause constipation Nausea, with occasional vomiting is common and is usually temporary Breasts enlarge rapidly, tingle and may even ache because of hormone changes Changes in cervix cause vaginal discharge Top of uterus may be felt above pubic bone after 12 weeks Tests may include: Complete history, Rh-Factor, Rubella, Blood type, and Pap smear. Weight gain - 1.4 kg
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•
Period of adjustment and doubt Difficulty accepting that partner is pregnant until she "shows" May feel bewildered, unable to understand partner's mood swings Needs to realize that contradictory feelings are normal Needs to understand possible sexual desire of woman Occasionally may get morning sickness or other symptoms experienced by the pregnant woman Both should feel satisfied with the choice of physician
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Unit Two: Prenatal Development 12th Week
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Eyes almost developed, but fused Smiles and frowns Permanent tooth buds forming Bones hardening Fingers and toes formed Arms and legs kicking Ears present Breathing movements Gender becomes apparent Thin skin develops Liver begins to function Can urinate Length - 10 centimeters Weight - 60 grams
Second Trimester 16th Week
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20th Week
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Greasy, cheesy substance on skin Blackish-green material collecting in intestine, called meconium Rapid brain growth Fine hair on body Sucks thumb, swallow and grasp reflex present Strong heart beat Active muscles Thin, transparent skin Length - 15 cm Weight - 170 grams Hair on head Physician can hear heart beat Hair, eyelashes and eyebrows form Fingernails and toenails formed Movements felt by mother Internal organs are maturing rapidly Length - 20 cm Weight - 300 grams
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•
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Time of acceptance and planning; think of baby as a person Mother usually feels exceptionally well and may experience increased interest in sexual activity Begins to look pregnant, may feel baby moving; may feel Braxton-Hicks contractions One third more blood volume May be anemic May leak milk May develop brownish blotches on face - chloasma Dark line down centre of abdomen Uterus enlarging causes increased pressure on legs; also signs of pressure on digestive system such as constipation Stretch marks may appear Vaginal discharge increasing Weight gain - 5 Kg
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•
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•
Time of acceptance of pregnancy; begins planning for lifestyle changes Plans should be made for childbirth education and type of delivery experience desired Enjoys the feeling of well-being of mother and, as she begins to look pregnant, feels protective toward her May react to partner's changing body with uneasiness or with great satisfaction
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Unit Two: Prenatal Development 24th Week
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Enamel forming in teeth Physician can feel baby's outline Skin wrinkled and red, covered with protective coating (vernix) Fat starting to deposit under the skin Eyes open Length - 30 cm Weight - 700 grams
Third Trimester 28th Week
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If born, baby could survive Adding baby fat Looks old and wrinkled Primitive breathing movements Length - 36 cm Weight - 1.1 Kg
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Has periods of extreme excitement and some doubt about impending motherhood Thinks of the baby as a person with a name and prepares the nursery and layette May feel baby's hiccup Increased uterine size upward may cause shortness of breath which is relieved in the 9th month when "lightening" occurs Fatigue or feelings of physical awkwardness may necessitate modification of sexual activity. However, intercourse is generally safe until the membrane erupts Desire for and frequency of sexual activity may decrease Baby sitting lower in abdomen (lightening) makes breathing easier but may also lead to urinary frequency and constipation Pressure on nerves, muscles and blood vessels may cause leg cramps, varicosities and aches in perineum and thighs
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•
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Probably feels proud of mother and catches her feelings of excitement May feel fear of responsibility towards parenthood May feel jealous of all the attention lavished on the woman and the baby and may feel left out Attending childbirth classes may reduce anxiety and fears about the labour process May feel that sexual relations will injure mother or baby. It is important to keep communication channels open May have difficulty in accepting and adapting to mother's physical and emotional changes Should decide whether or not to stay with partner during labour and delivery
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Unit Two: Prenatal Development 32nd Week
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36th Week
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•
Storing calcium Longer fingernails Testes descend into scrotum Hiccups Has periods of sleep and wakefulness Responds to sound Bones of head are soft and flexible Length - 40 cm Weight - 1.5 Kg. Storing iron and calcium Baby rounding out Muscle tone present Less active Length - 46 cm Weight - 2.5 Kg
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Hormones cause softening of tissues of cervix, vagina, and pelvic floor which may lead to feelings of distention or engorgement of pelvic floor Braxton-Hicks contractions may be very noticeable. Mother may experience false labour in last few weeks of pregnancy. There may also be dizziness from circulatory changes, and breasts are full of colostrum, the forerunner of true milk Total weight gain: 9 to 16 Kg.
Source: Rosetown Health Region, Saskatchewan Health, Community Services
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Unit Two: Prenatal Development
Cloning: A Twist on Creation By Rupert Taylor Scientists are on the brink of finding ways to cure some of our nastiest diseases, but their research, though fascinating, is highly controversial.
Dolly the sheep proved cloning to be possible in 1996. Many scientists were excited that their experiment worked. It wasn’t the first time a mammal, including sheep and cows, had been cloned though. A decade earlier it was shown that it was possible to take a fertilized egg (an embryo), from cattle or sheep, allow it to divide a few times, and then remove individual cells from the embryo. Each cell could then be inserted into a host egg (one which had its nuclear DNA removed) and given a small electrical jolt to fuse the transplanted DNA into the host egg. Thus, the process of cell division can be started. The egg develops into an embryo, which is transferred into a surrogate mother. In Dolly’s case, scientists took cells from the udder of a pregnant six-yearold ewe to insert into unrelated host eggs that had their DNA removed: instead of creating exact copies of a single, fertilized egg, they created a close copy of an adult animal. It took about 400 tries, but finally Dolly developed into a clone of her mother, something that scientists had long thought was impossible. Within a nanosecond of the announcement of the creation of Dolly came the question “Can we do the same for humans?” Probably yes, but a more important question is “Should we?” In a 2000 survey, 80% of Canadians said cloning for organs such as skin, hearts, or livers is acceptable, as long as the cloned organs are for treating injuries such as severe burns, in the case of skin, or for transplants. But, while most Canadians don’t have a problem with the idea of
cloning human parts for medical emergencies, about 90% of those surveyed said they were opposed to scientists making a genetically identical copy of a human being. More than 90% also said genetic engineering to pre-select the sex of an unborn child was unacceptable. And, about 74% didn’t like the idea of using genetic engineering to change the eye colour or other physical features of an unborn baby. But, the majority said it was okay for scientists to use biotechnology to cure an inherited medical condition, or to decrease the risk of illness.
Two Views In 1999, scientists reported that Dolly and two other clones of the Finn Dorset sheep she was cloned from, had cellular traits suggesting they would be sicker, age faster, or die sooner than those conceived naturally. But a year later, in April 2000, scientists published the results of a project in which the cells of six cloned calves were actually “younger” than their age. The cloning procedure seems to have given the calves cells that are biologically younger than their chronological age. Scientists don’t understand why his happened and they can’t say how fast the cells were aging, so they won’t know for years whether or not the calves will live longer than a cow’s normal 25 years. Researchers are hoping these developments will help them find ways of reversing degenerative conditions and cloning new human body parts—everything from lungs to livers—when the old ones fail. Page 11
Unit Two: Prenatal Development A bill that would have banned cloning humans died before the 1997 election. However, by August 2000, the federal government had developed a plan to try to win public backing for new rules on genetic and reproductive technologies. The expected legislation is likely to reflect Canadians’ wishes to ban human cloning and create a new national agency that would regulate the creation of test-tube babies and other reproductive practices. The next question is, should we depend on government regulation to protect us? The European Patent Office granted a German patent for the production of genetically modified humans, and almost immediately had second thoughts. After some reflection, the Germans decided that not only was granting the patent a serious mistake, it was also contrary to German law: in February 2000, the office admitted to having regrets about the patent. Six months later, Britain’s chief medical officer recommended that scientists be allowed to clone human embryos for medical research that he called “therapeutic cloning.” Using fetal tissue for medical research with a possible view to using it to grow new organs makes a lot of people cringe; most of the fetal tissue comes from aborted fetuses. Anti-abortion groups are frantic about the development. In July 2000, U.S. groups condemned the American Heart Association’s decision to invest heavily in research in human embryonic stem cells. This holds the promise of revolutionary treatments for countless conditions, including heart disease, Alzheimer’s, and blindness. Basically, an embryo is a cluster of microscopic stem cells, formed shortly after conception, which grows into a fetus. At this point, the stem cells start specializing to create a nervous system, spine, and other features. U.S. biologists announced that in 1998 that they had isolated human embryonic stem cells, explaining that they can multiply indefinitely before differentiating to form all the tissues and organs that make up the human body. By taking stem cells from the embryo before they start to specialize, scientists hope to direct them to
become any desired cell or tissue type. So astounding was the discovery that the medical journal Science declared that stem cell research was the most significant advance of 1999, which could dramatically change medical science. Child Selection It was reported in early October 2000 that an American couple chose to produce a child that could help save his older sister. The parents had several embryos created in a lab and selected the one that was free of a genetic disease that his sister has. He also was chosen because he was the best tissue match for his six-year-old sibling who needs a transplant to fight Fanconi anemia, a rare genetic disease that could be fatal because she cannot create her own bone marrow. In the first known case of its kind, doctors at the University of Minnesota infused blood from the umbilical cord of the five-week-old baby into his sister. At the time of writing, doctors didn’t know if stem cells contained in the newborn’s cord blood would help his sister develop healthy marrow cells. Anti-abortionists, and others, are not impressed. They fear that scientists will not only use the stem cells of aborted fetuses but start to artificially create life only to destroy it for research purposes. Either way they see the process as grossly unethical. As far as Rev. Joseph Howard, director of a division of the American Life League, is concerned, “There is no ethical way to obtain stem cells from a human embryo and there are no exceptions to this statement.” However, at least one group sides with patients who might benefit from the research. The Patients Coalition for Urgent Research in the U.S. is lobbying Congress to allow fetal tissue and stem cell research to go ahead. Not everyone sees the use of fetal tissue for research as an ethical dilemma. Dr. Steven Bamforth, a geneticist at the University of Alberta in Edmonton, says fetal tissue is like any other kind of organ donation. “Using an organ from someone killed by a drunk Page 12
Unit Two: Prenatal Development driver does not condone drinking and driving,” he says. “The fact that researchers use fetal tissue does not mean they condone abortion.” Dr. Bamforth runs Canada’s only fetal tissue repository, which sends parts of aborted fetuses to a small number of scientists across the country. While he doesn’t see this as a problem, he says if the majority of Canadians find it unacceptable, then the government should step in and end it.
A Monkey, is a Monkey, is a Monkey, is a Monkey … In September 1999, researchers at the Oregon Regional Primate Research Centre created a rhesus monkey in a lab using a technique called embryo splitting, in which cells are taken from a fertilized egg, split and transferred into surrogate mothers, producing animals that are genetic copies of the original embryo. The monkey, named Tetra, was the first cloned primate ever born, and scientists say that cloning monkeys will help them solve some of the mysteries of human disease.
The key to the dilemma might be within ourselves. In Canada, the Ottawa Hospital Research Institute has asked the federal government for up to $5 million to create a network of stem cell researchers in Canada, according to a Globe and Mail article. The group says it plans to concentrate on the idea that everyone has a limited number of stem cells in different parts of the body that can regenerate, including muscle, blood, and the brain. If these could be made to behave like embryonic stem cells then our own bodies could provide cures for whatever ails us. Using animal organs is another possibility researchers are looking into. In March 2000, five cloned piglets were born in Virginia. Scientists saw the event as the first step in supplying identical pig organs that are genetically engineered to be compatible with
human bodies. Some estimate there could be $6 billion (U.S.) market for pig organs, including heart, lungs, and liver, in a world desperately short of organ donors. With government approval, clinical trials with pig organs could start in four years: researchers still have to work on manipulating various pig genes to prevent organ rejection in humans, and some experts are checking out whether or not animal viruses concealed in pig DNA could possibly spread to human recipients. While the piglets were born in the United States, the idea for them came from PPL Therapeutics. PLC, the commercial firm responsible for Dolly the sheep. The company is based at the Roslin Institute, near Edinburgh, Scotland. PPL already has one flock of sheep producing a human protein used in treating cystic fibrosis. A second flock produces a protein that seals wounds and stops bleeding, and a third flock is making human enzyme that breaks down fats needed by people with pancreatic damage. The enzyme is also produced in mother’s milk, so it could also help premature babies that cannot be breast fed. The University of Guelph in Ontario is among those breeding pigs with a difference: they have an inserted human gene to help safely transplant organs into people. The pigs were developed in Britain by Imutran Ltd. and first imported into Canada in 1998. But, there are still problems with our immune systems rejecting human organs, let alone those from another, even genetically engineered, species. There also are fears that pig organs may carry viruses (such as porcine endogenous retro-viruses (PERV), a leukemia-like disease found in pigs) that can’t be treated in humans. There may also be a concern that such viruses might spread to other people. To many, crossing the species barrier is just plain wrong. But, that doesn’t stop the research by scientists who see animal transplants—known as xenotransplantation—as the answer to a critical need for organs, especially kidneys.
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Unit Two: Prenatal Development And, this just in! As we go to press, Italian scientists too have been looking for the answer from within. They now say they have found a way of isolating brain stem cells in adult rats. Potentially, these brain stem cells could be
Fact File •
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In 1998, doctors at a South Korean fertility clinic reported that they had taken the first step toward cloning a human. They said they made a four-celled embryo that was a clone of an infertile woman, but they didn’t implant the embryo in a woman’s uterus to see if it would grow. Using animals in the human health business has become known as “pharming.” Jonas Salk relied on cells from an aborted fetus in the 1930s to develop the polio vaccine. Given all the controversy there are no known Canadian scientists working the human embryonic stem cells. Researchers don’t want to risk losing much-needed funding so they keep their experiments to animal embryonic stem cells. While most Canadians are against human cloning, they tend to look favourably on reproductive technologies such as egg and sperm donation and surrogacy arrangements.
used to grow new lungs, or kidneys, or whatever tissue is needed. If the process can be transferred to humans, there may be no need to use fetal tissue at all, as those on both sides of the issue have hoped. Source: Canada and the World Backgrounder, October 2000
Making connections …. •
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The U.S. has legislated against producing human clones but Canada has not. Patricia Baird, a geneticist at the University of British Columbia and chairwoman of the 1993 Royal Commission on New Reproductive Technologies said in a Globe and Mail interview that if Canada did have legislation in place prohibiting human cloning “you would not be so worried about animal experimentation (leading to human cloning).” Do a report on what the Commission has been doing since its inception. Ian Wilmut, one of the scientists who created Dolly the sheep at the Roslin Institute in Scotland, says the cells from which stem cells are derived are embryonic in nature, with no evidence of the formation of a nervous system. In an article in The Globe and Mail in February 2000, he wrote that “the human nervous system will not begin to form until several weeks into a normal pregnancy. As the embryo is not yet aware, it is a potential person, but not yet a person in that critical sense. In these circumstances, I would consider using the cells of human embryo.” Dr. Wilmut points out that, under British law, a human embryo has special status, but not that of a full human being. But, he adds that “any use of human embryos should be subject to ethical scrutiny, nationally or locally,” and that the country’s Human Fertilization and Embryology Authority “scrutinizes everything done with a human embryo whether for clinical or research purposes.” • Discuss his view on using human embryos for research. • What does Canadian law say about the issue of fetal rights? • What are the legal issues involved in the Page 14 question of fetal rights?
Unit Two: Prenatal Development
A Double-Edged Sword By
Rupert J. and Linda E. Taylor Scientific developments often present society with new moral dilemmas, perhaps never more so than with the decoding of the human genome. "Science in the service of society". That's a slogan with a nice ring to it. Images spring to mind of barren landscapes made suddenly fertile, or people ravaged by disease quickly cured. Science performs those miracles and many more. But, science and the way it's used isn't always for the best. This issue has been brought into sharp focus by the decoding of the human genome. For a decade, more than a thousand scientists worked to unlock the biological secrets held within the roughly 100,000 genes that, together, form the basis of human life. With great fanfare, the completion of the project was announced in June, 2000. Before the genome project began in 1990 most of the genetic construction of humans was a mystery. It was as though someone had taken the only copy of the instruction manual for making people, stripped each page of its letters, jumbled them up, thrown them into a cellar, and switched the lights off. Scientists then had to grope about in the dark and reassemble the manual without even knowing what the original copy looked like. The fact that the job was completed in ten years owes more to computer technology than biology. At the start of 1999, scientists in a branch of technology called bioinformatics developed the capacity to sequence 1,000 letters of DNA per second, 24 hours a day, seven days a week. That breakthrough got the project into the fast lane. The decoding process was a joint effort, involving scientists from the United Kingdom, the United
States, China, France, Germany and Japan. Its completion was treated as a great moment in history, so Britain's Prime Minister Tony Blair and American President Bill Clinton jointly made the announcement through a transatlantic telephone hookup. However, understanding the location and function of each gene is only the start. A great deal of work remains to be done. A large number of diseases are caused by genetic flaws, or by the absence of one or more genes. Having the complete instruction manual will help scientists solve many medical mysteries. Within a couple of decades, doctors could be able to cure many cancers that today are usually fatal. Such illnesses as Alzheimer's, Parkinson's, multiple sclerosis, schizophrenia, diabetes, and many others may also be conquered. Dr. Francis Collins is Director of the Human Genome Project (HUGO). He says that by 2040, gene therapy and genebased drugs will be available for most diseases, and the average human life span will reach 90. In July 2000, The Economist wrote about a brighter future for medicine. "These days the talk is of a perfect diagnosis, drugs that will work first time and have no side-effects, even of predictive medicine so accurate that it could tell you, should you want to know, when you are going to die and of what." That's the good news. But, the information coming out of HUGO raises a lot of ethical questions. One of the major ones turns on money.
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Unit Two: Prenatal Development Jean Paul Getty (1892-1976) put together a vast fortune in the oil business. Recently, one of his grandsons made the observation that "Intellectual property is the oil of the 21st century." Companies protect the value of their intellectual property (their discoveries or innovations) through patents. A patent prevents anyone else from using the breakthrough without payment to its owner. This protection encourages biotechnology companies to undertake very expensive research because they are assured of a financial payoff if the research proves successful. A patent gives its holder a monopoly in the same way as a right to drill for oil on a particular parcel of land. Without patent protection there would be little reason for commercial interests to begin research.
Genome 101 Deoxyribonucleic acid is such a mouthful that most people just call it DNA. James Watson and Francis Crick discovered DNA in 1953 inside tiny X-shaped structures called chromosomes. Each person has 23 pairs of chromosomes in the nucleus of cells that make up their body. The DNA molecule is two chains of chemical compounds called polynucleotides. The chains are twisted into the form of a coil, called a double helix. Between the twisted strands of DNA are structures that look like the rungs of a ladder. These are called bases and they come in pairs. The bases are coded with the letters A, C, G, and T, which relate to their chemical composition. A section of DNA with a four letter combination of bases forms a gene; a single gene can have thousands of base pairs. The chemical instruction carried by a coded gene determines whether a cell will become part of a toenail or part of an ear lobe, for instance. There are thought to be about 100,000 genes in each person (nobody knows for sure how many) and this is called the human genome.
Figure 1: Deoxyribonucleic acid, DNA The issue is full of high drama; it involves life, death and big money. To see why, let's look at the story of a bacterium called Staphylococcus aureus. This bacteria causes Toxic Shock Syndrome, an infection that usually proves fatal if untreated. But, Staph aureus is a clever little devil that develops resistance to the ever-more powerful antibiotics that are used against it. In the early 1990s, doctors at Harvard University began the search for a way of attacking the bacterium. They realized the key to an effective treatment was unlocking the Staph aureus genome, but they lacked the funding for such a project. Then, in 1996, a private company announced that it had decoded the Staph aureus genome. But, the Harvard scientists were denied access to it. Human Genome Sciences Inc., kept the genome secret to ensure that it got all the money out of its discovery that it could before sharing it with anyone else. Three other biotech companies did the same thing. Harvard pleaded for public funding to help unlock the Staph aureus secret. The project eventually got its money and, early in 1999, the bacterium's genome was sequenced and a vaccine produced. But, how many people died during the two-tothree-year period it took for the public discovery of the genome? Philosopher Alex Wellington and political scientist Ted Schrecker summed up the dilemma in a March 2000 article in the Globe and Mail.
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Unit Two: Prenatal Development "Questions remain," they wrote, "about the appropriate balance between private returns…and the public interest. Fairness dictates that the inventors and investors should benefit from their commitments of money and scientific knowledge. But their returns should not be determined only by what the market will bear." Many people - scientists, religious leaders, philosophers, ethicists, and others - question whether or not a life form can, or even should be, patented. Dr. Gert-Jan van Ommen of Leiden University in the Netherlands says, "A mere DNA molecule…cannot constitute an invention." However, by April 2000, an estimated 40,000 genetic patents were pending at the U.S. Patent and Trade Office. Canadian law is beginning to catch up to this challenge. The Canadian Patent Act says that intellectual property rights may be asserted over "any new and useful art, process, manufacture or composition of matter." There's no mention of life forms. But, in simple terms, a patent application only has to pass three tests; is the invention new, useful and non-obvious? In the case of the Harvard mouse the Canadian Court of Appeal answered "yes" to all three. In August 2000, the Court ordered that a patent be issued on the mouse which has been genetically tweaked to make it more prone to cancer, making it valuable to medical researchers. It took 15 years for the case to get this far, and the court ruled only on whether the mouse met the tests for patentability. The Court of Appeal judges said that there might well be good reasons that living things should not be patented. But, that's an issue for elected officials to decide, not the courts. To which politicians will say under their breath, "Thanks a lot." It'll be a monster for legislators to tackle, because no matter what decision is made somebody will be ticked. Environmentalists and a large portion of the general public are very
suspicious of genetics and biotechnology. But, multi-national companies are very gung-ho to push the science forward. Some experts get nervous about genetic technology for other reasons. One is genetic screening. This can be done today for some conditions and it will become more commonplace in the near future. Careful study of a sample of DNA can reveal how likely a person is to succumb to certain illnesses. One of these ailments for which a screening test is already available is Huntington disease. It is a genetic brain disorder that affects one in 10,000 people. If one parent of a child has Huntington's disease and the other does not, the child has a 50% chance of inheriting the disease. Once transmitted, it is almost certain to develop and it is always fatal. If Huntington's occurred in your family would you have the genetic test done? In Canada, only one in five at risk people wants to know if the Huntington gene has been transmitted to them. There's nothing sinister about the personal choice of whether to know or not know. Where the moral dilemma creeps in is whether anybody else should know; and this applies to all genetic screening. People applying for jobs today usually fill out an application form in which they reveal some personal information - age, marital status, previous employment, etc. Companies choose whom to hire based, to some extent, on this information. What if employers could add genetic screening to the hiring process? This would inevitably lead to genetic discrimination. Given two equally qualified applicants would a company hire the one whose genetic screening revealed a likelihood of developing schizophrenia? Probably not. Genetic screening information could also be used to deny someone insurance. But, why would that be a problem? Insurance companies already delve into a person's medical history when writing life or health coverage. A person who has suffered a heart attack is going to have trouble getting life
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Unit Two: Prenatal Development insurance. Concealing an existing heart ailment would probably make the insurance invalid. Genetic screening would simply give insurance companies more accurate information than they have now. Another concern is the possibility of creating "designer babies." Today, when a sperm and an egg unite, chance plays a major role in how the life thus created will turn out. The embryo will get half its genes from its mother and half from its father. Whether it inherits its father's tallness or its mother's blue eyes pretty much depends on a roll of the dice. But, genetic engineering holds within it the promise of overcoming the random nature of heredity. We might be able to fix the problem with chromosome 21. Most people have an identical second copy of chromosome 21, but occasionally a third copy appears. This extra chromosome 21 is the cause of Down's syndrome, a form of mental retardation. It's possible that the third copy of chromosome 21 could be removed and the baby born without Down's syndrome. Most people would agree that eliminating Down's syndrome is a positive development. The same with thalassemia and Tay-Sachs disease. Both illnesses usually kill victims before adulthood and both are inherited. A blood test can determine the odds of a couple having affected children. A screening project for thalassemia and Tay-Sachs disease has been underway in Montreal since the 1970s. Researchers say the program has reduced the incidence of the diseases by 95%.
carrier. Do you call off the wedding because any children you might have together are more likely to die young? The tests can also be done on an unborn fetus. If it's positive do you have an abortion? These are troubling questions for many people. The questions get even more troubling when we confront the possibility of creating "designer babies." Germ-line manipulation is the scientific term for this and it's done soon after an egg has been fertilized. It involves taking the very earlyembryonic cells apart to see what the genetic lottery has delivered to them. (This process destroys the cells and puts new focus on the question of when life begins.) Any genetic material that is seen as defective - presumably, the parents decide what's good and what's bad - can then be snipped out and replaced. At present, this is a very difficult trick to pull off, but it will become easier and accurate. We know that certain human characteristics will be preferred: tall over short, male over female, good looking over average, smart over dumb. Will society go along with a concept that allows parents to order up a child with options in the same way as they can order up a hamburger or a car today? On the other hand, who wouldn't want to get a pet unicorn for a birthday present? Taylor, R. "Social Concerns", Canada and the World Backgrounder, Volume 66, No. 2, October 2000.
But, suppose you are a carrier of thalassemia and you fall in love with another
Making connections …. •
Gattaca, is the title of a 1997 science fiction movie about a world in which a person's DNA determines his or her place in the social structure. It is a world of cooled-down emotions and soft-spoken terror, in which the world's leaders and achievers have been genetically engineered as test tube babies to "be the best that they can be." Natural-born people are called "In- Valids" because they are more likely to carry imperfections, weaknesses and diseases. They are second-class citizens, shut out of meaningful society. Should society genetically engineer cognitive and emotional perfection in its leaders? Discuss the issue. Page 18
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Labour and Delivery This article describes the process of labour and delivery, the culmination of 38 weeks of phenomenal growth and development, the emergence of a brand new member of the human race! The time has arrived! After what for most parents has seemed like an eternity, all of the hopes, dreams and potentials of the human race will be realized again with the birth of this child. This article will describe the amazing process of labour and delivery. What are the stages of birth? The birth process occurs in three stages: • For a woman having her first child, the first stage, the longest, lasts an average of 12 to 24 hours. Uterine contractions are 15 to 20 minutes apart at the beginning and last up to a minute. These contractions cause the woman’s cervix to stretch and open. As the first stage progresses, the contractions come closer together, appearing every 2 to 5 minutes. Their intensity increases too. By the end of the first birth stage, these contractions dilate the cervix to an opening of about 8 to 10 centimeters. This allows the baby to move from the uterus to the birth canal. • The second stage begins when the baby’s head starts to move through the cervix and the birth canal. It terminates when the baby completely emerges from the mother’s body. This stage lasts approximately 2 hours. With each contraction, the mother bears down hard to push the baby out of her body. By the time the baby’s head is out of the mother’s body, the contractions come almost every minute and last for about a minute. • Afterbirth is the third stage, at which time the placenta, umbilical cord and other membranes are detached and expelled.
This final stage is the shortest of the three birth stages, lasting only minutes. (Santrock, 1999) What are the strategies used in childbirth? • In the standard childbirth procedure, the expectant mother is taken to a hospital where a doctor is responsible for the baby’s delivery. • The Leboyer method intends to make the birth process less stressful for infants. Leboyer vehemently objects to holding newborns upside down and slapping them, putting silver nitrate in their eyes, separating them immediately from their mothers, and scaring them with bright lights and harsh noises in the delivery room. In the Leboyer method, the baby is placed on the mother’s stomach immediately after birth so the mother can caress the infant. Then the infant is placed in a bath of warm water to relax. • The Lamaze method has become a widely used childbirth strategy. It involves helping the expectant mother to cope actively with the pain of childbirth through relaxation and breathing techniques, and to avoid or reduce medication. (Santrock, 1999) • A caesarian section is the surgical removal of the baby from the uterus. A caesarian section is usually performed if the baby is in a breech position, if it is lying crosswise in the uterus, if the baby’s head is too large to pass through the mother’s pelvis, if the baby develops complications, or if the mother is bleeding vaginally. (Santrock, 1999)
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Unit Two: Prenatal Development What are some of the complications that arise in labour and delivery? • Precipitate delivery is a form of delivery that takes place too rapidly. A precipitate delivery is one in which the baby takes less than 10 minutes to be squeezed through the birth canal. This deviation in delivery can disturb the infant’s normal flow of blood, and the pressure on the infant’s head can cause hemorrhaging. • Anoxia, insufficient supply of oxygen to the infant, can develop if the delivery takes too long. Anoxia can cause brain damage. • The breech position is the baby’s position in the uterus that causes the buttocks to be the first part to emerge from the vagina. Normally, the crown of the baby’s head comes first. (Santrock, 1999) What is the father’s role in the labour and delivery process? In the past several decades, fathers have increasingly participated in childbirth. Fathers-to-be are now more likely to go to at least one meeting with the obstetrician or care-giver during the pregnancy, attend childbirth preparation classes, learn about labour and delivery, and be more involved in the care of the young infant. For many expectant couples today, the father is trained to be the expectant mother’s coach during labour, helping her to learn relaxation methods and special breathing techniques for labour and birth. (Santrock, 1999) The degree of involvement and initiative a husband shows in performing these activities defines his role as either an active coach or passive observer. There are three roles most often assumed by men during the labor and delivery process that provides varying amounts of social support to their wives. These roles are: 1. Coach • Most frequently ASSIGNED role to mother's partner; few partners
actually and adequately perform expectations • Expected to actively assist with breathing, relaxation, and pain control • Leads and directs mom by modeling breathing techniques and facilitating proper contraction response • Moms look to Coaches for encouragement and directions 2. Teammate • Participate by responding to support requests made by laboring mom. • Look for directions from medical staff to follow. • Encourage more medical involvement than coaches because they have a lesser need for situational control. 3. Witness • Most commonly CHOSEN role by husbands because it allows for togetherness without the pressure of being in control of the birthing process. • Role is detached - for husbands who are afraid of being sick or have trouble watching their wives in pain. • Men who witness the birth are fulfilling their own curiosity about the experience, performing their social obligation, and bonding with their infant BUT they do little to participate in the experience. These roles that husbands choose are directly related to the interaction style and the interpersonal dynamics of the couple's relationship before pregnancy. The couple's levels of interdependence, sharing, and understanding are often predictors of the male's role during childbirth. Chapman (1992) identified that "Witnesses" have the lowest levels of the relationship qualities mentioned above. Why is the male's role during childbirth important to understand?
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Unit Two: Prenatal Development • •
•
There is often a mismatch between the role assigned to the male and the role he would choose for himself Childbirth is a stressful experience for women - social support has been shown to buffer the negative effects of the intense stress - spousal support is the most often requested support by women (Nichols, 1993 & Keinan & Hobfoll, 1989). Women should receive the support they desire to deal with the stress of childbirth and yet men should be able to participate in the experience at a level they feel comfortable (Swinney, 2000)
Summary Giving birth is no less important than the preceding 9 months of pregnancy, and it too is fraught with many issues, challenges and potential dangers. Technology has made a significant impact on the birth process, enabling doctors and nurses to monitor the baby while still in the womb and detect fetal stress or other possible complications. So too, the changing role of the father and other support systems has changed the process of labour and delivery. Fathers, and even immediate family members such as siblings, are now being actively involved in labour and delivery.
Making connections …. • •
•
Create a comparison chart describing alternate forms of birthing, as well as their strengths and limitations. Based on Swinney's article regarding the father's role in childbirth (see Teacher Information) what changes have occurred during the last few decades? Talk to your father. What was his role in the labour and delivery process? Talk to your grandfather. What was his experience? Talk to your mother. What was the labour and delivery process like when she had you? Talk to your grandmother. What was her experience? Discussion: • Given the possible complications that might arise during labour and delivery, why would some expectant mothers choose to stay at home and deliver their babies?
References: Chapman, L.L. (1991). Expectant fathers' roles during labor and birth. JOGNN, 21(2), 114-120. Keinan, G., & Hobfoll, S.E. (1989). Stress, dependency, and social support: who benefits from husband's presence in delivery? Journal of Social and Clinical Psychology, 8(1), 32-44. Nichols, M.R. (1993). Paternal perspectives of the childbirth experience. Maternal Child Nursing Journal, 21(3), 99-108. Palkovitz, R. (1987). Father's motives for birth attendance. Maternal Child Nursing Journal, 16(2), 123-129. Shapiro, J.L. (1987). The expectant father. Psychology Today, 21(1), 36-42.
Recommended reading: Chapman, L. (1991). Searching: Expectant fathers' experience during labor and birth. Journal of Perinatal and Neonatal Nursing, 4, 21-29. Feher, L. (1988). Birth issues. Birth Psychology Bulletin, 9, 21-25. Keirse, M., Enkin, M., & Lumley, J. (1989). Social and professional support during labor. In I. Chalmers, M. Enkin, & M. Keirse (Eds.), Effective care in pregnancy and childbirth, (pp. 53-61). New York: Oxford University Press. Miller, B., & Bowen, S. (1982). Father- to-newborn attachment behavior in relation to prenatal classes and presence at delivery. Family Relations, 31, 71-78.
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Looking through the eyes of the system of supports…. What do you see? This article describes the various support systems that work together to support and nurture healthy prenatal development. Using Bronfenbrenner's Ecological Model (1979), this article will describe how each of the various levels of supports work to nurture and promote healthy prenatal development.
The developing baby is surrounded by various levels of support systems that work to promote and support healthy prenatal development. Without a doubt, the most important of these is the mother, who through the umbilical cord, is linked directly with the fetus. What role does the mother play in the healthy development of the unborn child? Research suggests five proactive steps that mothers can take to ensure that the baby has the very best chance to develop properly: 1. Abstinence from alcohol, drugs and tobacco even before pregnancy. 2. Abstinence after the first trimester: The effects of drugs accumulate throughout pregnancy. Thus, early prenatal care would reduce fetal brain damage substantially. In fact, because the last trimester of pregnancy is critical for brain development, a drug-free second half of pregnancy may be enough to prevent brain damage if drug use during the first half was moderate.
that is reduced, each drug that is eliminated, and each day that is drug- free, represents a reduction in the damage that can be caused. 4. Social support: Maternal stress, psychological problems, loneliness and poor housing correlate with prenatal complications as well as with drug use. Befriending, encouraging and assisting pregnant drug users may not only reduce their use of teratogens (substances and conditions that increase the risk of abnormalities) but also, even without directly affecting drug use, aid fetal development. 5. Postnatal care: Another way to protect children from suffering the consequences of their mother's prenatal drug use is to ensure sensitive nurturance after birth through parenting education, preventive medicine, home visits, early day care and if necessary, foster care) (Berger, 2000) Even though not physically connected to the baby, the father also has a very important role to play in supporting healthy development.
3. Moderation throughout pregnancy: Since the prenatal of psychoactive drugs are doserelated, interactive and cumulative, each dose
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Unit Two: Prenatal Development
First Trimester • • • • • •
•
Period of adjustment and doubt Difficulty accepting that partner is pregnant until she "shows" May feel bewildered, unable to understand partner's mood swings Needs to realize that contradictory feelings are normal Needs to understand possible sexual desire of woman Occasionally may get morning sickness or other symptoms experienced by the pregnant woman Both should feel satisfied with the choice of physician
Second Trimester • • •
•
Time of acceptance of pregnancy; begins planning for lifestyle changes Plans should be made for childbirth education and type of delivery experience desired Enjoys the feeling of well-being of mother and, as she begins to look pregnant, feels protective toward her May react to partner's changing body with uneasiness or with great satisfaction
Third Trimester • • •
•
•
•
•
Probably feels proud of mother and catches her feelings of excitement May feel fear of responsibility towards parenthood May feel jealous of all the attention lavished on the woman and the baby and may feel left out Attending childbirth classes may reduce anxiety and fears about the labour process May feel that sexual relations will injure mother or baby. It is important to keep communication channels open May have difficulty in accepting and adapting to mother's physical and emotional changes Should decide whether or not to stay with partner during labour and delivery
The importance of the father in helping to minimize maternal stress cannot be understated. In addition, the establishment of the connection between "Dad" and baby begins even in the womb. The baby is able to differentiate sounds during the last trimester, and so will respond to the sound of the father's voice immediately after birth. From the father's perspective, establishing that paternal bond will last for a lifetime. No father can forget the first time he felt the baby move in its mother's tummy.
(Shapiro, 1987 & Chapman, 1991). Father's are currently expected to be more involved in childbirth and child care activities than they have in the recent past. Today, it is rare to find a father who is not present for the birth of his child. (Shapiro, 1987). How can husbands help during childbirth? • Provide emotional support • Provide encouragement and comfort • Give directions • Provide instrumental support
The presence of "Dad's to be" during childbirth is a new tradition. The 1990's mark the fortieth anniversaries of both the Prepared Childbirth and the Women's Movements that have greatly influenced the paternal role in child raising.
The degree of involvement and initiative a husband shows in performing these activities defines his role as either an active coach or passive observer. There are three roles most often assumed by men during the labor and
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Unit Two: Prenatal Development delivery process that provides varying amounts of social support to their wives. These roles are: • Coach • Most frequently ASSIGNED role to mother's partner; few partners actually and adequately perform expectations • Expected to actively assist with breathing, relaxation, and pain control • Leads and directs mom by modeling breathing techniques and facilitating proper contraction response • Moms look to Coaches for encouragement and directions • Teammate • Participate by responding to support requests made by laboring mom • Look for directions from medical staff to follow • Encourage more medical involvement than coaches because they have a lesser need for situational control • Witness • Most commonly CHOSEN role by husbands because it allows for togetherness without the pressure of being in control of the birthing process • Role is detached - for husbands who are afraid of being sick or have trouble watching their wives in pain • Men who witness the birth are fulfilling their own curiosity about the experience, performing their social obligation, and bonding with their infant BUT they do little to participate in the experience These roles that husbands choose are directly related to the interaction style and the interpersonal dynamics of the couple's relationship before pregnancy. The couple's levels of interdependence, sharing, and understanding are often predictors of the male's role during childbirth. Chapman (1992) identified that "Witnesses" have the lowest levels
of the relationship qualities mentioned above. Why is the male's role during childbirth important to understand? • There is a mismatch between the role assigned to the male and the role he would choose for himself • Childbirth is a stressful experience for women - social support has been shown to buffer the negative effects of the intense stress - spousal support is the most often requested support by women (Nichols, 1993, Keinan & Hobfoll, 1989). • Women should receive the support they desire to deal with the stress of childbirth and yet men should be able to participate in the experience at a level they feel comfortable The school and community can both play a vital role in supporting healthy prenatal development. School programs for teen moms such as Millie’s Early Learning Centre at Nutana Collegiate in Saskatoon, provide for both the baby and mom, helping to ensure that the career choices of the mother are not limited by pregnancy and the demands of raising a newborn child. The community, particularly through Health Agencies, provides numerous support services to expectant mothers and fathers, not the least of which are prenatal classes. In addition, special programs such as Healthy Babies, Healthy Moms, as well as Students and Kinds Services (S.A.K.S.), provide on-going support and education to expectant parents. While the mother, father, community and Health Agencies can all work together to help support the developing baby, larger factors such as economics also play a significant role in prenatal development. • Poverty and policy interact to affect the rate of infants born weighing under 2.5 kilograms, as reported in a sample of 148 nations to the United Nations in 1998.
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•
Generally, the nations of Europe do best on this indicator of national health, and those of Southern Asia worst. Compared with women of higher socioeconomic status, pregnant women at the bottom of the economic ladder are more likely to be ill, malnourished, teenaged and stressed. They often receive late or inadequate prenatal care, breathe polluted air, live in overcrowded conditions, move from
place to place and ingest unhealthy substances. Poor women have less access to family planning services, and they live in communities that encourage higher birth rates, partly because these communities have higher death rates. In this way, the social context may underlie many of the biological causes of low birthweight. (Berger, 2000, 120)
Making connections ……… •
•
•
• •
What changes have occurred in prenatal care during the last few decades? Talk to your mother. What was her experience in preparing for childbirth? What support services were available to her? Talk to your father. What was his role in the labour and delivery process? Talk to your grandfather. What was his experience? Talk to your mother. What was the labour and delivery process like when she had you? Talk to your grandmother. What was her experience? Legal issues in prenatal development • When is a fetus considered a person, with rights under the Canadian Charter of Rights and Freedoms? • If a mother is a substance abuser, and her addiction will undoubtedly harm the child, should the government have the right to apprehend the mother to ensure that the baby is able to develop properly? Dialectical Reasoning: Universal Maternity leave • Thesis: All expectant mothers should be given paid maternity leave for the duration of their pregnancy to promote healthy development of the baby. • Antithesis: The economic cost to the country is too great, expectant mothers should be educated in prenatal development, and then the responsibility for healthy development is theirs. Teen pregnancy: • What are the provincial and national statistics on teen pregnancy? • What specific issues and challenges do teen parents face? "In the Ghetto", recorded by Elvis Presley - The lyrics discuss the cycle of violence and poverty of a child born into a ghetto. • What messages does this song have for the role and influence of the socio-cultural environment in terms of human development?
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Unit Two: Prenatal Development
Influences on prenatal development While the developing child is relatively insulated from the outside world while in the womb, still, there remain many possible factors and agents that can seriously, and often negatively, influence development. This article describes the wide range of substances and conditions, called teratogens, which influence prenatal development. There are many sources of potential harm to both developing baby and mother. Ranging from environmental concerns such as toxic chemicals, fumes and poisons, to drugs including smoking and alcohol, the delicate nature of prenatal development can often be jeopardized. What are some influences that impact on healthy prenatal development? Teratogens are the broad range of substances (such as drugs and pollutants) and conditions (such as severe malnutrition and extreme stress) that increase the risk of prenatal abnormalities. These abnormalities include obvious physical problems (such as missing limbs) and more subtle impairments such as brain damage that first appears in elementary school. A specific teratogen may damage the body structures, the growth rate, the neurological networks, or all three. Teratogens that harm the brain, and therefore make a child hyperactive, antisocial, retarded and so on, are called behavioural teratogens; their effects can be far more damaging over the life of a person than physical defects. (Berger, 2000) What are the factors that influence the degree of affect? One crucial factor is when the developing organism is exposed to which teratogen. Some teratogens cause damage only during specific days or weeks early in pregnancy, when a particular part of the body is undergoing formation. Others can be harmful at any time, but how severe the damage is depends on when the exposure occurred. The time of greatest susceptibility is called the critical period.
Each body structure has its own critical period. As a general rule, for physical defects the critical period is the entire period of the embryo. (Berger, 2000) A second important factor is the dose and/or frequency of exposure to a teratogen. For most teratogens, experts are reluctant to specify a threshold below which the substance is safe. One reason is that many teratogens have an interaction effect; that is, one poison intensifies the effects of another. (Berger, 2000) A third factor that determines whether a specific teratogen will be harmful, and to what extent, is the developing organism's genes. In some cases, genetic vulnerability is related to the sex of the developing organism. Generally, male embryos (XY) embryos and fetuses are at a greater risk than female in that more male embryos are more often aborted spontaneously. In addition, newborn boys have more birth defects, and older boys have more learning disabilities and other problems caused by behavioural teratogens. (Berger, 2000) What are some of the specific influences that may affect prenatal development? Radiation, chemicals and other hazards in the environment can endanger the fetus. Chromosomal abnormalities are higher among the offspring of fathers exposed to high levels of radiation in their occupations. Environmental pollutants and toxic wastes are also sources of danger to unborn children. Among the dangerous pollutants and wastes are carbon monoxide, mercury and lead. Another environmental concern is toxoplasmosis, a mild infection that causes coldlike symptoms or no apparent illness in adults,
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Unit Two: Prenatal Development but can cause eye defects, brain defects and premature birth. Cats are common carriers of toxoplasmosis, especially outdoor cats who eat raw meat. The expectant mother may pick up the virus through the cat litter box. (Santrock, 1999) In terms of the mother’s age, two time periods are of special interest: adolescence and the thirties and beyond. Infants born to adolescents are often premature. The mortality rate of infants born to adolescent mothers is double that of infants born to mothers in their twenties. Down Syndrome, a form of mental retardation, is related to the mother's age. By age 40, the probability is slightly over 1 in 100. By age 50, it is almost 1 in 10. The risk is also higher before age 18. Women also have more difficulty in becoming pregnant after the age of 30. (Santrock, 1999) A developing fetus depends completely on its mother for nutrition, which comes from the mother's blood. Among the important factors are the total number of calories and the appropriate levels of protein, vitamins and minerals. The mother's nutrition even influences her ability to reproduce. In extreme instances of malnutrition, women stop menstruating. Also children born to malnourished mothers are more likely to be malformed. (Santrock, 1999) Another common reason for slow fetal growth - and hence low birthweight - is maternal malnutrition, a problem that has many specific causes. Women who begin pregnancy underweight, eat poorly during pregnancy, and consequently do not gain at least 1.5 kilograms per month in the second and third trimesters run a much higher risk than others of having a low-birthweight infant. Indeed, women who gain less than 7 kilograms, even if they are non-smokers who begin pregnancy overweight, still have a higher risk of preterm and smaller babies than those who gain at least 7 kilograms. (Berger, 2000)
example, the greatest damage to the fetus from the mother contracting German measles occurs during the 3rd and 4th weeks of pregnancy. Syphilis is more damaging later in pre-natal development - 4 months or more after conception. Rather than affecting organ development as Rubella does, syphilis damages organs after they have formed. The importance of the mother's health to the health of their offspring is nowhere better exemplified than when the mother is infected with HIV. (Santrock, 1999) Drugs includes the use of tobacco, alcohol, prescription or illegal drugs. For example, the effects of thalidomide during the fourth week of development had devastating effects. Heavy drinking by an expectant mother can also be devastating. Fetal alcohol syndrome is a cluster of abnormalities that appear in the offspring of mothers who drink alcohol heavily during pregnancy. The abnormalities include facial deformities and defective limbs, face and heart. Most of these children are below average in intelligence. In one study, however, even mothers who drank moderately during pregnancy had babies who were less attentive and alert, with the effects still present at 4 years of age. Cigarette smoking by pregnant women can also adversely influence pre-natal development, birth and postnatal development. Fetal and neonatal deaths are higher among smoking mothers. Also prevalent are a higher incidence of preterm births and lower birthweights. Respiratory problems and sudden infant death syndrome are also more common among the offspring of mothers who smoked during pregnancy. Tranquilizers taken during the first three months may cause cleft palate or other congenital malformations. Mothers who take large amounts of barbituates may have babies who are addicted or may exhibit tremors, restlessness and irritability. (Santrock, 1999)
Maternal diseases and infections can produce defects by crossing the placental barrier. For
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Prenatal Development Drug Alcohol
Usage 3 or more drinks daily, or binge drinking of 5 or more drinks on one occasion early in pregnancy
More than ½ ounce of absolute alcohol a day
Tobacco
Moderate drinking: less than 1 or 2 servings of beer or wine or 1 mixed drink on a few days per week Maternal smoking early in pregnancy Maternal smoking late in pregnancy
Paternal smoking
Compared with women of higher socioeconomic status, pregnant women at the bottom of the economic ladder are more likely to be ill, malnourished, teenaged, and stressed. Physical difficulty like malfunction of the placenta or the umbilical cord is likely when pregnancies are closely spaced and close spacing correlates with poverty. Poverty helps explain the wide national and international variations in the following statistics: • Of the more than 25 million low-birthweight infants born worldwide each year, the overwhelming majority are in developing countries. • Developing countries in the same geographic region, with similar ethnic populations, have
•
•
Effects Causes fetal alcohol syndrome (FAS). Symptoms include abnormal facial characteristics (small head, wide spacing between the eyes, a flattened nose, a narrow upper lip, unusual eyelids), overall growth retardation, learning disabilities and behaviour problems. Causes fetal alcohol effects (FAE). FAE does not obviously affect facial appearance or physical growth, but it affects brain functioning. Probably has no negative effects on prenatal development, although this is controversial Increases risk of abnormalities, including malformations of the limbs and the urinary tract Reduces birthweight and size. Babies born to habitual smokers weigh, on average, about 250 grams less than they would otherwise be expected, and they are shorter, both at birth and in the years to come. They may have childhood problems, particularly with respiration and, in adulthood, increased risk of becoming smokers themselves. Reduces birthweight by about 45 grams on average
markedly different low-birthweight rates when they have different average incomes. Within nations, differences in lowbirthweight rates among ethnic groups follow socioeconomic differences among those groups. Within the United States, low birthweight rates in the poorest states are almost twice those in some richer states. (Berger, 2000)
The mother's stress can be transmitted to the fetus. When a pregnant woman experiences intense fears, anxieties and other emotions , physiological changes occur in the fetus. These include changes in respiration and glandular secretions. For example, producing adrenaline in
Unit Two: Prenatal Development response to fear restricts blood flow to the uterine area and may deprive the fetus of adequate oxygen. Also, reassuring the mother of fetal well-being has positive outcomes for the infants in the study. (Santrock, 1999) Are there times during pregnancy when the effect of teratogens is especially important? As was previously mentioned, not only is the specific teratogen important in determining the effects on prenatal development, but so is the time during pregnancy when the teratogen influences the fetus. This is referred to as a critical period. The table below describes the
Body System Central Nervous System/Brain Heart Upper limbs Eyes Lower limbs Teeth Palate External Genitalia Ears
critical periods for fetal development for the major organs and body systems. Summary Teratogens represent the broad range of substances and conditions that can seriously impact prenatal development. Ranging from environmental conditions such as toxic chemicals and radiation to specific substances such as tobacco and alcohol, the delicate nature of prenatal development can be compromised and the effects of that impairment last a lifetime.
Especially Sensitive 4th to 8th weeks 5th to 9th weeks 6th to 10th weeks 6th to 10 weeks 6th to 10th weeks 9th to 11th weeks 9th to 11th weeks 9th to 11th weeks 6th to 11th weeks
Development up to … Postnatal, through to adulthood 12th week 12th week Term 12th week Term 16th week Term 13th week
Making connections ….. • • •
Research: Fetal Alcohol Syndrome • What are the differences between F.A.S and F.A.E.? • What are the physical, mental and emotional effects of fetal alcohol syndrome? Research: Down Syndrome • What are the causes of Down Syndrome? • What are the challenges that people with Down Syndrome face? Discussion: Generally, male embryos (XY) embryos and fetuses are at a greater risk than female in that more male embryos are more often aborted spontaneously. In addition, newborn boys have more birth defects, and older boys have more learning disabilities and other problems caused by behavioural teratogens. • Why? What could be some factors in this situation?
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The life-span approach to prenatal development This article considers how the life span approach to development can be used as a conceptual organizer to describe the developmental process from conception to birth. From the perspective of the life-span approach, human development can be described as seven intertwined spirals, each one of which continuously complements and supports the others. As we move across the life-span, so each of these aspects influences our development. At times, one or more of these aspects may be brought to bear in such a way that their influence is greater, for example, in times of Depression and poverty where food is in short supply, so the process of human development is more strongly affected. The life-span approach does not only apply to the physical development, but also to the mental, emotional and spiritual aspects as well. Similarly, in times of great stress, or sadness and grief, laughter, love and intimacy, our development is influenced and we change and grow. The life-span perspective on human development has seven basic characteristics. Development is: • • • • • • •
Life-long, no age period dominates development; Multidimensional, development consists of biological, cognitive and socio-emotional dimensions; Multidirectional, some aspects of development increase, while others decrease (for example, during adulthood decision-making skills improve, while memory decreases); Plastic, depending on the individual's life conditions, development may take many paths; Historically embedded, development is influenced by historical conditions (The Great Depression, Wars, Poverty); Multidisciplinary, psychologists, sociologists, anthropologists, neuroscientists and medical researchers all study human development and share a concern for unlocking the mysteries of development throughout the life span; Contextual, the individual continually responds to and acts on contexts, which include a person's biological makeup, physical environment, and social, historical, and cultural contexts.
Using the template on the following page as a guide, in what ways does the life-span approach to development apply to prenatal development? For each of the seven aspects of the life-span approach to development, can you find an example that satisfies the description?
Making connections …….. •
Using any medium of your choice, draw, construct or create a graphic that symbolizes or represents the seven strands in the life-span approach to human development.
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The life-span approach to prenatal development Multidimensional ….
Life long ….
Plastic ….
Multidirectional ….
Historically embedded ….
Contextual ….
Multidisciplinary ….
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My Anthology
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Unit Two: Prenatal Development
From both perspectives …… Topic: Cloning of human organs for transplant should be allowed. Reasons why I agree…
Reasons why I disagree …
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