Maternal and neonatal outcomes of antihypertensive treatment in pregnancy: A retrospective cohort study

by Sascha Dublin, Abisola Idu, Lyndsay A. Avalos, T. Craig Cheetham, Thomas R. Easterling, Lu Chen, Victoria L. Holt, Nerissa Nance, Zoe Bider-Canfield, Romain S. Neugebauer, Kristi Reynolds, Sylvia E. Badon, Susan M. Shortreed

Objective

To compare maternal and infant outcomes with different antihypertensive medications in pregnancy.

Design

Retrospective cohort study.

Setting

Kaiser Permanente, a large healthcare system in the United States.

Population

Women aged 15–49 years with a singleton birth from 2005–2014 treated for hypertension.

Methods

We identified medication exposure from automated pharmacy data based on the earliest dispensing after the first prenatal visit. Using logistic regression, we calculated weighted outcome prevalences, adjusted odds ratios (aORs) and 95% confidence intervals, with inverse probability of treatment weighting to address confounding.

Main outcome measures

Small for gestational age, preterm delivery, neonatal and maternal intensive care unit (ICU) admission, preeclampsia, and stillbirth or termination at > 20 weeks.

Results

Among 6346 deliveries, 87% with chronic hypertension, the risk of the infant being small for gestational age (birthweight < 10th percentile) was lower with methyldopa than labetalol (prevalence 13.6% vs. 16.6%; aOR 0.77, 95% CI 0.63 to 0.92). For birthweight < 3^rd percentile the aOR was 0.57 (0.39 to 0.80). Compared with labetalol (26.0%), risk of preterm delivery was similar for methyldopa (26.5%; aOR 1.10 [0.95 to 1.27]) and slightly higher for nifedipine (28.5%; aOR 1.25 [1.06 to 1.46]) and other β-blockers (31.2%; aOR 1.58 [1.07 to 2.23]). Neonatal ICU admission was more common with nifedipine than labetalol (25.9% vs. 23.3%, aOR 1.21 [1.02 to 1.43]) but not elevated with methyldopa. Risks of other outcomes did not differ by medication.

Conclusions

Risk of most outcomes was similar comparing labetalol, methyldopa and nifedipine. Risk of the infant being small for gestational age was substantially lower for methyldopa, suggesting this medication may warrant further consideration.