As I was going through the literature for effects of antihypertensives in pregnancy I came across a paper by Li et al which challenges the effect of ACE inhibitors and ARBs on occurrence of congenital malformation in the foetus in first trimester. Li and his colleagues retrospectively analysed a data in half a million mother-infant pair in the Kaiser Permanente Northern California region from 1995 to 2008 to examine a reported association between use of angiotensin converting enzyme (ACE) inhibitors during the first trimester and risk of malformations in offspring. Li and colleagues studied the incidence of heart defects in four groups: (i) the overall population, (ii) those on ACE inhibitors, (iii) those on other antihypertensive agents, and (iv) a final group who were hypertensive but not on treatment1.
After adjustment for maternal age, ethnicity, parity, and obesity, use of ACE inhibitors during the first trimester only seemed to be associated with increased risk of congenital heart defects in offspring compared with normal controls (those with neither hypertension nor use of any antihypertensives during pregnancy) (3.9% v 1.6%) cases, odds ratio 1.54 (95% confidence interval 0.90 to 2.62)). Cardiac defects were present in 1.6% of controls, 3.9% on ACE inhibitors, 2.6% on other antihypertensives, and 2.4% of hypertensives not on any therapy. Thus, compared with controls (no hypertension and no treatment), any hypertension, treated or not, seems to be a risk factor for offspring with a cardiac defect1.
They also concluded maternal use of ACE inhibitors in the first trimester has a risk profile similar to the use of other antihypertensives regarding malformations in live born offspring. The apparent increased risk of malformations associated with use of ACE inhibitors (and other antihypertensives) in the first trimester is likely due to the underlying hypertension rather than the medication1.

Reference:

1. Li DK, Yang C, Andrade S, Tavares V, Ferber JR Maternal exposure to angiotensin converting enzyme inhibitors in the first trimester and risk of malformations in offspring: a retrospective cohort study. BMJ. 2011 Oct 18;343:d5931. doi: 10.1136/bmj.d5931 .

Competing interests: None declared