Thalidomide

Date: September 2022, Version 3

Quick read

Thalidomide should never be used in pregnancy as it causes serious birth defects in the baby.

What is it?

Thalidomide was introduced in the 1950s to treat sleeping problems and morning sickness. It was withdrawn in the early 1960s as it causes severe birth defects if taken during early pregnancy. However, thalidomide is now being used to treat multiple myeloma (a cancer of the blood that most commonly affects older people) and in some developing countries to treat leprosy.

Is it safe to take thalidomide in pregnancy?

No. Thalidomide use in early pregnancy, particularly around 5-7 weeks after the last period, can cause severe birth defects in the baby.

Women and girls who need to take thalidomide and who may become pregnant are therefore required to be in a pregnancy prevention programme (PPP). This usually includes:

Agreeing to use reliable contraception, or to abstain from sexual intercourse during treatment and for one month afterwards.
Having a negative pregnancy test before starting treatment, and then having repeat pregnancy tests every month during treatment and one month after treatment has stopped.
Signing a consent form to say that your doctor has explained the risks to a pregnancy of thalidomide treatment and that you understand these risks.

Because thalidomide stays in the body for some time after you stop taking it, it is important to avoid getting pregnant for at least one month after the last dose.

What if I have already taken thalidomide during pregnancy?

If you are pregnant or think you may be pregnant and are taking thalidomide you should urgently contact your doctor or midwife.

What problems are caused by taking thalidomide in pregnancy?

A large number of different birth defects have been reported in children of women who took thalidomide in pregnancy. Abnormalities of the hands and arms are most commonly seen and include a very specific abnormality termed phocomelia (where the hands are attached close to the body and the arms are absent or under-developed).

The following birth defects have also been linked to thalidomide:

Phocomelia of the legs/feet
Missing thumbs, or thumbs with an extra bone
Club feet
Extra toes
Reduced or missing ears and deafness
Paralysis of facial nerves
Abnormally small eyes and other eye malformations
Heart defects
Defects of the internal organs, including kidneys, brain, digestive and reproductive systems (it is not certain whether all of these birth defects were caused by thalidomide)

Some children exposed to thalidomide have one of these birth defects while some have several. The type and number of birth defects relates to the exact stage of pregnancy when thalidomide was taken and how many times it was used, although birth defects have been reported following a single dose.

Thalidomide use in pregnancy has also been linked to miscarriage and stillbirth.

Will my baby need extra monitoring during pregnancy?

Most women will be offered a scan at around 20 weeks of pregnancy to look for birth defects as part of their routine antenatal care.

Women who have taken thalidomide in the month before pregnancy or during the first trimester and who decide to continue with their pregnancy will be offered more detailed anomaly scans and additional monitoring of the baby’s growth and wellbeing.

Are there any risks to my baby if the father has taken thalidomide?

When a man takes thalidomide, small amounts enter his semen. Men taking thalidomide are therefore advised to use condoms during sexual contact with pregnant women or women of childbearing potential because of the possibility that thalidomide in semen may pose a risk to a developing baby.

Who can I talk to if I have questions?

If you have any questions regarding the information in this leaflet, please discuss them with your health care provider. They can access more detailed medical and scientific information from www.uktis.org.

How can I help to improve drug safety information for pregnant women in the future?

Our online reporting system (MyBump Portal) allows women who are currently pregnant to create a secure record of their pregnancy, collected through a series of questionnaires. You will be asked to enter information about your health, whether or not you take any medicines, your pregnancy outcome and your child's development. You can update your details at any time during pregnancy or afterwards. This information will help us better understand how medicines affect the health of pregnant women and their babies. Please visit the MyBump Portal to register.

General information
Sadly, miscarriage and birth defects can occur in any pregnancy.

Miscarriage occurs in about 1 in every 5 pregnancies, and 1 in every 40 babies are born with a birth defect. This is called the ‘background risk’ and happens whether medication is taken or not.

Most medicines cross the placenta and reach the baby. For many medications this is not a problem. However, some medicines can affect a baby’s growth and development.

If you take regular medication and are planning to conceive, you should discuss whether your medicine is safe to continue with your doctor/health care team before becoming pregnant. If you have an unplanned pregnancy while taking a medicine, you should tell your doctor as soon as possible.

If a new medicine is suggested for you during pregnancy, please make sure that the person prescribing it knows that you are pregnant. If you have any concerns about a medicine, you can check with your doctor, midwife or pharmacist.

Our Bumps information leaflets provide information about the effects of medicines in pregnancy so that you can decide, together with your healthcare provider, what is best for you and your baby.