Antihypertensive medication use during pregnancy and the risk of major congenital malformations or small-for-gestational-age newborns.

BACKGROUND

In spite of the widespread use of antihypertensives during pregnancy, data on their risks and benefits for the newborn are limited. We investigated the risk of major congenital malformations or small-for-gestational-age newborns (SGA) in relation to gestational use of antihypertensives.

METHODS

Within the Quebec Pregnancy Registry, we conducted two case-control studies. First, cases were defined as major congenital malformations diagnosed during the first year of life and controls were selected from the same cohort; index date was date of delivery. Gestational exposure was defined as filling a prescription for an antihypertensive during the 1st trimester of pregnancy. Next, cases (SGA) were defined as newborns with a birth weight <10th percentile for that gestational age and gender; controls were the newborns with a birth weight > or =10 percentile. Gestational exposure was defined as filling a prescription for an antihypertensive during the 2nd or 3rd trimester. Multivariate logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (95% CI).

RESULTS

We found that overall antihypertensives use during the 2nd or 3rd trimesters of pregnancy was associated with a higher risk of SGA (OR 1.53, 95% CI 1.17-1.99). Moreover, selective beta-blocker (OR 6.00, 95% CI 1.06-33.87), alpha beta blocker (OR 2.26, 95% CI 1.04-4.88), or centrally-acting adrenergic agents use (OR 1.70, 95% CI 1.00-2.89) was associated with a higher risk of SGA compared to non-use.

CONCLUSION

Gestational use of antihypertensives, especially beta-blocker, alpha beta blocker, or centrally-acting adrenergic agents, may increase the risk of SGA.