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.