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Date of issue: May 2023, Version: 2

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A corresponding patient information leaflet on USE OF CALCIUM CHANNEL BLOCKERS IN PREGNANCY is available.

Calcium channel blockers (CCBs) (amlodipine, diltiazem, felodipine, lacidipine, lercanidipine, nicardipine, nifedipine, nimodipine, and verapamil) are mainly used for the treatment of hypertension and for the treatment and prophylaxis of angina. Additionally, nifedipine is used to treat Reynaud’s phenomenon and as a tocolytic to delay or prevent premature labour; nimodipine is used for the prevention and treatment of subarachnoid haemorrhage; verapamil is used to treat supraventricular arrhythmias and for the prophylaxis of cluster headaches. Topical diltiazem (2%) is used off-license to treat anal fissure.

The National Institute for Health and Care Excellence (NICE) guidelines on hypertension in pregnancy suggest that nifedipine may be given as an alternative, or in addition to labetalol.

While data on overall rates of fetal structural malformation or certain specific malformations (including heart defects) following first trimester use of CCBs do not suggest increased risks, data are limited.

Rates of miscarriage do not appear to be increased following exposure to CCBs in early pregnancy. However, further research is required to confirm this finding. Available data do not support an increased risk of intrauterine death following exposure to nifedipine in pregnancy; however, further studies are required to confirm this and IUD/stillbirth risk for other CCBs. Data on rates of preterm delivery, fetal growth and neurodevelopmental outcomes are limited but do not raise any particular concerns.

CCBs are routinely used in pregnancy to treat hypertension and may also be used in the management of threatened preterm labour. Exposure to a CCB at any stage in pregnancy would not usually be regarded as medical grounds for termination of pregnancy. In pregnancies complicated by maternal hypertension or threatened preterm labour, additional fetal monitoring may be required, depending on the clinical situation. Other risk factors may also be present in individual cases which may independently increase the risk of adverse pregnancy outcome. Clinicians are reminded of the importance of consideration of such factors when performing case-specific risk assessments.

This is a summary of the full UKTIS monograph for health care professionals and should not be used in isolation. The full UKTIS monograph and access to any hyperlinked related documents is available to NHS health care professionals who are logged in.

If you have a patient with exposure to a drug or chemical and require assistance in making a patient-specific risk assessment, please telephone UKTIS on 0344 892 0909 to discuss the case with a teratology specialist.

If you would like to report a pregnancy to UKTIS please click here to download our pregnancy reporting form. Please encourage all women to complete an online reporting form.

Disclaimer: Every effort has been made to ensure that this monograph was accurate and up-to-date at the time of writing, however it cannot cover every eventuality and the information providers cannot be held responsible for any adverse outcomes of the measures recommended. The final decision regarding which treatment is used for an individual patient remains the clinical responsibility of the prescriber. This material may be freely reproduced for education and not for profit purposes within the UK National Health Service, however no linking to this website or reproduction by or for commercial organisations is permitted without the express written permission of this service. This document is regularly reviewed and updated. Only use UKTIS monographs downloaded directly from to ensure you are using the most up-to-date version.