Pregnancy protection and pregnancies in women prescribed ACE inhibitors or ARBs: a cross-sectional study in primary care

Background The teratogenic risks of angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) are well documented, but prescribing these in younger women in primary care is becoming increasingly frequent.

Aim To record how frequently women of childbearing age, who are prescribed an ACE inhibitor or ARB, receive preconception advice and/or are prescribed contraception, and how many pregnancies, terminations, and miscarriages occur in this population. Additionally, to ascertain whether patterns in the above differ across age groups.

Design and setting Cross-sectional study conducted among patients from 141 general practices in East London.

Method Women aged 15–45 years who were issued a prescription for an ACE inhibitor or ARB between 1 October 2018 and 1 January 2019 inclusive were included. An electronic search strategy was designed to extract pseudonymised data concerning preconception and contraception advice, contraception, and pregnancies from the electronic clinical system; this was applied to the selected cohort on 1 January 2019. Data were analysed in 5-year age groups.

Results Of 302 939 women aged 15–45 years, 2651 (0.9%) were prescribed an ACE inhibitor or an ARB in a 3-month period. Of these, 2159 (81.4%) had no advice and no contraception prescription recorded, 35 (1.3%) had preconception advice recorded, and 230 (8.7%) had contraception advice recorded. A total of 100 pregnancies and 21 terminations/miscarriages were recorded in the 12 months preceding the index date (1 January 2019).

Conclusion This study found that the recording of pre-pregnancy advice and contraception in women of childbearing age who were prescribed an ACE inhibitor or an ARB was suboptimal; this may place women and their babies at risk of exposure to teratogens during pregnancy. The findings indicate that there is a need for improved safety strategies based in primary care.