(Date: May 2020. Version: 2)

This factsheet has been written for members of the public by the UK Teratology Information Service (UKTIS). UKTIS is a not-for-profit organisation funded by the UK Health Security Agency (UKHSA) on behalf of UK Health Departments. UKTIS has been providing scientific information to health care providers since 1983 on the effects that medicines, recreational drugs and chemicals may have on the developing baby during pregnancy.

What is it?

Methyldopa (Aldomet®) is used to treat high blood pressure (hypertension) in pregnancy.

What are the benefits of taking methyldopa in pregnancy?

Methyldopa can prevent the complications caused by hypertension (high blood pressure) in pregnancy, and a related condition called pre-eclampsia. These complications include preterm birth, low birth weight in the baby, and illness in both the mother and baby which is sometimes serious.

Are there any risks of taking methyldopa during pregnancy?

Use of methyldopa in pregnancy is common and is unlikely to cause any harm. Most pregnant women taking methyldopa will start treatment after the first trimester when the baby is fully developed. This will therefore not cause structural birth defects in the baby. Even if you have taken methyldopa in the first trimester, there is no good evidence that this is linked to birth defects. There are also no known links with miscarriage or stillbirth and no evidence that methyldopa causes preterm birth or low infant birth weight.

Are there any alternatives to taking methyldopa?

Possibly. Other medicines can also be used to treat hypertension in pregnancy and pre-eclampsia. However, if your doctor has suggested that you take methyldopa, this will be based on a number of factors including how you have responded to other high blood pressure medicines and whether you have experienced any side effects. If you have any questions about a medicine that you are offered in pregnancy, you should discuss them with your doctor or midwife.

What if I prefer not to take medicines to treat hypertension or pre-eclampsia?

It is very important to take any medicines prescribed for hypertension or pre-eclampsia as both of these conditions can be serious for both mother and baby. Your doctor will only prescribe medicines when absolutely necessary and will be happy to talk to you about any concerns that you might have.

Will my baby need extra monitoring?

All pregnant women in the UK should be offered a detailed anomaly scan at around 20 weeks of pregnancy as part of their routine antenatal care. No extra monitoring for major birth defects is required following methyldopa use in pregnancy.

In general, women with high blood pressure will be more closely monitored during pregnancy to ensure that they remain well throughout and that their baby is growing as expected.

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

We would not expect any increased risk to your baby if the father takes methyldopa.

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

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General information 

Up to 1 out of every 5 pregnancies ends in a miscarriage, and 1 in 40 babies are born with a birth defect. These are referred to as the background population risks.  They describe the chance of these events happening for any pregnancy before taking factors such as the mother’s health during pregnancy, her lifestyle, medicines she takes and the genetic make up of her and the baby’s father into account.

Medicines use in pregnancy

Most medicines used by the mother will cross the placenta and reach the baby. Sometimes this may have beneficial effects for the baby.  There are, however, some medicines that can harm a baby’s normal development.  How a medicine affects a baby may depend on the stage of pregnancy when the medicine is taken. If you are on regular medication you should discuss these effects with your doctor/health care team before becoming pregnant.

If a new medicine is suggested for you during pregnancy, please ensure the doctor or health care professional treating you is aware of your pregnancy.

When deciding whether or not to use a medicine in pregnancy you need to weigh up how the medicine might improve your and/or your unborn baby’s health against any possible problems that the drug may cause. Our bumps leaflets are written to provide you with a summary of what is known about use of a specific medicine in pregnancy so that you can decide together with your health care provider what is best for you and your baby.   

Every pregnancy is unique. The decision to start, stop, continue or change a prescribed medicine before or during pregnancy should be made in consultation with your health care provider. It is very helpful if you can record all your medication taken in pregnancy in your hand held maternity records.

Disclaimer: This information is not intended to replace the individual care and advice of your health care provider. New information is continually becoming available. Whilst every effort will be made to ensure that this information is accurate and up to date at the time of publication, we cannot cover every eventuality and the information providers cannot be held responsible for any adverse outcomes following decisions made on the basis of this information. We strongly advise that printouts should NOT be kept for any length of time, or for “future reference” as they can rapidly become out of date.

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