Patient Information

Venous thrombosis in pregnancy and after birth

Author: Maternity Produced and designed by the Communications Team Issue date Apr 2013 - Review date Apr 2016 - Expiry date Apr 2017

Version 1 Ref no. PIL1556

Who is at risk of venous thrombosis?

How is venous thrombosis diagnosed during pregnancy?

Pregnant women are ten times more likely

DVT

to develop venous thrombosis than

Your doctor will examine your leg and may

women who are the same age and not

offer you an ultrasound scan of your leg to

pregnant. Venous thrombosis related to

show where the clot is. If no clot is seen,

pregnancy can occur at any stage of

but you are still having symptoms, the

pregnancy and for six weeks after birth.

scan may be repeated after one week.

This is due to changes from being pregnant.

Pulmonary embolus The tests may include:

Additional risks for developing a venous

l

thrombosis in pregnancy are when you:

l

common problems which could be the

have had a previous venous

cause of your symptoms, such as a

thrombosis

l

a chest X-ray (this can also identify

chest infection)

have a condition called thrombophilia,

l

which makes a blood clot more likely

a CT scan (specialised X-ray) of your lungs

l

are over 35 years of age

l

are overweight – body mass index

your lungs. This needs a drip into a

(BMI) over 30

vein in your arm

l

l

l

are carrying more than one baby (multiple pregnancy)

l

have severe pre-eclampsia

l

have just had a caesarean delivery

l

are immobile for long periods of time,

l

a VQ scan (ventilation perfusion) of

an ultrasound of both your legs to look for an existing blood clot which may not have caused you any symptoms

Are there any risks with having the tests?

for example, after an operation or when

The chest X-ray, CT scan and VQ scan

travelling for four hours or longer

use radiation (X-rays). You may be concerned about the risk of these tests to

are a smoker

2

l

the baby. The chest X-ray uses a very small dose of radiation and the baby will

reduces the risk of a pulmonary embolus

be shielded. The risk to your baby of

l

developing cancer in childhood after a

reduces the risk of another venous thrombosis developing

VQ scan is extremely rare (1 in 280,000).

l

There are small risks with CT and

lowers the risk of long-term symptoms

VQ scans and these need to be weighed

developing in the leg, known as ‘post-

up against the risk to mother and baby of

thrombotic syndrome’ (see What

an undiagnosed venous thrombosis. A

happens after birth and can I

CT scan gives a higher dose of radiation

breastfeed?)

to your breasts than a VQ scan and the

What does heparin treatment involve?

lifetime risk of breast cancer may be increased. The risk may be increased by up to 13.6% with a background risk of

Heparin is given as an injection under the

1 in 200.

skin at the same time(s) every day. The dose is worked out for you according to

What is the treatment for venous thrombosis?

your weight before you became pregnant. You (or a family member) will be shown

As soon as your doctor suspects you have

how and where in your body to give the

a venous thrombosis, you will be advised

injections. You will be provided with the

to start on treatment with an injection of

needles and syringes (usually already

heparin (an anticoagulant) to ‘thin the

made up) and you will be advised on how

blood’. There are different types of

to store and dispose of these. You will

heparin. The most commonly used in

have regular check-ups, including blood

pregnancy is ‘low-molecular-weight

tests, as an outpatient. You will probably

heparin’ (LMWH).

not need to stay in hospital.

For most women, the benefits of heparin

How long will I need to take heparin?

are that it:

l

works to prevent the clot getting any bigger so your body can gradually

Treatment is usually recommended for the

dissolve the clot

remainder of your pregnancy and for at

3

least six weeks after the birth. The

What should I do when labour starts?

minimum treatment time is three months. Contact your doctor if you experience any

Most women with a DVT continue with

worrying symptoms when you are taking

their pregnancy normally. If you think that

heparin (such as chest pains, unexpected

you are going into labour, do not take any

bruises, a sudden change in your health).

more injections. Phone your hospital

Also contact your doctor if you have any

immediately and tell them that you are on

heavy bleeding during this time.

heparin treatment. They will advise you.

What else can help?

If the plan is to induce labour, you should

l

Stay as active as you can

stop your injections 24 hours before the

l

You will be prescribed a special

into the space around the nerves in your

stocking (graduated elastic

back) cannot usually be given until 24

compression stocking) which helps to

hours after your last injection. Alternative

reduce the swelling in the leg

pain relief options will be discussed. An

l

planned date. An epidural injection (given

individual plan will be made with you. If you need pain relief, ask your doctor or midwife

What if I have a planned caesarean delivery?

Are there any risks to me and my baby from heparin?

Your last heparin injection should be 24 hours before the planned caesarean

Low-molecular-weight heparin cannot

delivery (operation to deliver your baby).

cross the placenta to the baby and so is

The heparin will usually be re-started

safe to take when you are pregnant.

within 3 hours of the operation.

There may be some bruising where you

What happens after birth and can I breastfeed?

inject which will usually fade in a few days. One or two women in every 100 (1–2%) will have an allergic reaction when they

Treatment should be continued for at least

inject. If you notice a rash after injecting,

six weeks after you give birth. There is a

you should inform your doctor so that the

choice of treatment after birth of

type of heparin can be changed.

4

continuing with injections of heparin or

A glossary of all medical terms is available

using warfarin tablets. Your doctor will

on the RCOG website at

discuss your options with you.

www.rcog.org.uk/womens-health/patientinformation/medical-terms-explained

Both heparin and warfarin are safe to take when breastfeeding.

Sources and acknowledgements

After birth, you will usually be given an

This information is based on the Royal

appointment with your GP, obstetrician or

College of Obstetricians and

haematologist. At your appointment the

Gynaecologists (RCOG) guideline-

doctor will:

Thromboembolic Disease in Pregnancy and the Puerperium: Acute Management

l ask about your family history of

(published by the RCOG in February

thrombosis and discuss tests for a

2007). This information will also be

condition which makes thrombosis more

reviewed and updated if necessary once

likely (thrombophilia). These should be

the guideline has been reviewed. The

done ideally before any future

guideline contains a full list of the sources

pregnancies

of evidence we have used. You can find it

l discuss your options for contraception

online at: http://rcog.org.uk/files/rcogcorp/GTG37b_230611.pdf

(you should be advised not to take any contraception that contains estrogen, for

Clinical guidelines are intended to improve

example, the ‘combined pill’)

care for patients. They are drawn up by

l discuss future pregnancies: you will

teams of medical professionals and

usually be recommended heparin

consumer representatives who look at the

treatment during and after your next

best research evidence available and

pregnancy

make recommendations based on this evidence.

l give you information about a compression stocking: it is

This information has been developed by

recommended that you should wear this

the Patient Information Subgroup of the

on the affected leg for two years.

RCOG Guidelines and Audit Committee, with input from the Consumers’ Forum and the authors of the clinical guideline. It has been reviewed before publication by

5

women attending clinics in Salisbury,

A final note

Paisley and Bolton. The final version is the

The Royal College of Obstetricians and

responsibility of the Guidelines and Audit

Gynaecologists produces patient

Committee of the RCOG.

information for the public. This is based on guidelines which present recognised methods and techniques of clinical practice, based on published evidence. The ultimate judgement regarding a particular clinical procedure or treatment plan must be made by the doctor or other attendant in the light of the clinical data presented and the diagnostic and treatment options available.

6

7

Not to be photocopied

Basildon University Hospital Nethermayne Basildon Essex SS16 5NL ( 01268 524900 / 0845 155 3111 Minicom ( 01268 593190 Patient Advice and Liaison Service (PALS) ( 01268 394440 E [email protected] W www.basildonandthurrock.nhs.uk

The Trust will not tolerate aggression, intimidation or violence directed towards its staff. This is a smokefree Trust. Smoking is not allowed in any of our hospital buildings or grounds. This information can be provided in a different language or format (for example, large print or audio cassette) on request.