Date: March 2024, Version 3.0

Quick take

Flecainide can be used in pregnancy if prescribed by a specialist.

What is it?

Flecainide (Tambocor®) is used in people with an arrhythmia (an abnormal heart rhythm). Flecainide is also occasionally given to a pregnant woman to treat an abnormally fast heartbeat in the unborn baby.


What are the benefits of using flecainide in pregnancy?

Flecainide can reduce the chance of serious illness in women with an abnormal heart rhythm. It can also lower the chance of a poor pregnancy outcome by treating an abnormally fast heartbeat in the unborn baby.


Are there any risks of using flecainide during pregnancy?

Only a small number of pregnant women using flecainide have been studied. While no clear risks have been linked to its use, ongoing studies are ideally required. However, the conditions that flecainide is used to treat can be life-threatening to both the woman and her baby, so the benefits of use will usually outweigh any risks.


Are there any alternatives to using flecainide in pregnancy?

Possibly. A specialist will be able to advise on the best choice of medicine for each woman’s circumstances.

No treatment

What if I prefer not to use flecainide in pregnancy?

Flecainide use is only advised in pregnancy if it is the best choice of medicine to treat a potentially serious condition. The specialist prescribing flecainide will be happy to discuss any concerns you may have.

Will I or my baby need extra monitoring?

As part of their routine antenatal care, most women will be offered a scan at around 20 weeks of pregnancy to look for birth defects and to check the baby’s growth. Women with serious heart arrhythmias are likely to be monitored more closely during pregnancy to ensure that they remain well throughout and that their baby is growing and developing as expected. Where an abnormally fast heartbeat has been detected in the baby, extra monitoring will be required to determine the need for treatment and to ensure that the baby has not developed a condition called fetal hydrops. This is where abnormal fluid levels build up in the baby’s body due to the heart not working effectively.

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

No studies have specifically investigated whether flecainide used by the father can harm the baby through effects on the sperm; however, most experts agree that this is very unlikely. More research on the effects of medicine use in men around the time of conception is needed.

Who can I talk to if I have questions?

If you have any questions about 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.