Calcium channel blockers

(Date: July 2016. Version: 1)

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.

Quick read

Calcium channel blockers can be used in pregnancy to treat angina and high blood pressure.

What are they?

Nine calcium channel blockers are used in the UK: amlodipine (Istin®), diltiazem (Tildiem®, Adizem®, Angitil®, Dilcardia®, Slozem®, Uard®, Viazem®, Zemtard®), felodipine (Cardioplen®, Delofine®, Felotens®, Folpik®, Neofel®, Parmid®, Vascalpha®), lacidipine (Motens®, Molap®), lercanidipine (Zanidip®), nicardipine (Cardene®), nifedipine (Adipine®, Nifedipress®, Tensipine®, Dexipress®, Valni®, Adalat®, Adanif®, Neozipine®, Nidef®, Fortipine®), nimodipine (Nimotop®), and verapamil (Half Securon®, Vera-Til®, Verapress®, Securon®).

Calcium channel blockers are mainly used to treat angina and high blood pressure.

Nifedipine is used to treat Reynaud’s phenomenon (a circulatory problem), verapamil can also be used to treat an arrhythmia (irregular heartbeat) and to prevent cluster headaches, and diltiazem cream might be prescribed to treat anal fissure.

What are the benefits of using a calcium channel blocker in pregnancy?

Calcium channel blockers can prevent the pregnancy complications caused by high blood pressure and a related condition called pre-eclampsia. These complications include preterm birth, low infant birth weight, and illness in the mother and baby that can be serious.

Pregnant women with angina or an irregular heartbeat (arrhythmia) may need to continue using a calcium channel blocker to ensure that their heart remains healthy.

Use of a calcium channel blocker to treat Reynaud’s phenomenon, anal fissure, or to prevent cluster headaches can prevent the adverse effects on quality of life and wellbeing caused by these conditions.

What are the risks of using a calcium channel blocker in pregnancy?

There are no clear risks of taking a calcium channel blocker in pregnancy.

Nifedipine is commonly used in pregnancy and is unlikely to cause harm.

The other calcium channel blockers are less commonly used, and while not thought to cause problems, will only be recommended if the benefits of treating a potentially serious or lifestyle-impacting condition outweigh any possible risks.

Are there any alternatives to taking a calcium channel blocker in pregnancy?

Possibly. Other medicines can be used to treat high blood pressure or a heart problem in pregnancy but are not suitable for everyone. It is very important that these conditions are well-controlled, so staying on a calcium channel blocker might be the best option.

Women taking a calcium channel blocker for less serious conditions may be able to stop their medication during pregnancy.

Women who are taking a calcium channel blocker and planning a pregnancy, should speak to their doctor or specialist to make sure that it is ok to continue. No changes to medication should be made unless recommended by a doctor.

What if I prefer not to take medicines in pregnancy?

It is important to take any medicines prescribed for high blood pressure or heart problems as these conditions can be serious for both mother and baby. Untreated high blood pressure can cause preterm birth, low infant birth weight, and illness in the mother and baby that can be serious.  Additionally, it is vital for the woman’s wellbeing that any condition that greatly impacts quality of life remains as well-controlled as possible. A doctor will only prescribe medicines when necessary and will be happy to discuss any concerns.

Will I or my baby need extra monitoring?

As part of routine antenatal care, most women will be offered a very detailed scan at around 20 weeks of pregnancy to check the baby’s development. No extra monitoring for major birth defects is required following use of a calcium channel blocker.

In general, women with high blood pressure and/or heart problems will be more closely monitored during pregnancy to make sure 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 a calcium channel blocker?

There is no evidence that a calcium channel blocker used by the father can harm the baby through effects on the sperm.

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

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

Our online reporting system allows women with a current or previous pregnancy to create a digitally secure ‘my bumps record’. You will be asked to enter information about your health, whether or not you take any medicines, and your pregnancy outcome. 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 to register.

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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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