As in the general population, management of hypertension in pregnant women is complicated by factors that may be difficult to control (such as diabetes, obesity, and smoking). However, the choice of antihypertensive drug is uniquely complicated in pregnancy, because the clinician not only has to consider the comparative safety and efficacy of various drugs from the mother’s perspective, but also consider the effects on the fetus. Rising rates of hypertension related to obesity and diabetes heighten this concern. Furthermore, therapeutic choices cannot wait until pregnancy is recognised—because about half of pregnancies (at least in the United States) are unplanned, fetal exposure early in the first trimester is a distinct possibility. Thus, fetal concerns should be taken into account when prescribing antihypertensives to all women of childbearing potential—a considerable clinical population. In the linked retrospective cohort study (doi: 10.1136/bmj.d5931), Li and colleagues assess the association between the use of angiotensin converting enzyme (ACE) inhibitors in mothers during the first trimester and the risk of malformations in their offspring.1

Few studies have been large and …