Adverse Maternal and Infant Outcomes in Women With Chronic Hypertension in France (2010-2018): The Nationwide CONCEPTION Study.

Background It has been suggested that chronic hypertension is a risk factor for negative maternal and fetal outcomes during pregnancy and postpartum. We aimed to estimate the association of chronic hypertension on adverse maternal and infant outcomes and assess the impact of antihypertensive treatment and these outcomes. Methods and Results Using data from the French national health data system, we identified and included in the CONCEPTION cohort all women in France who delivered their first child between 2010 and 2018. Chronic hypertension before pregnancy was identified through antihypertensive medication purchases and by diagnosis during hospitalization. We assessed the incidence risk ratios (IRRs) of maternofetal outcomes using Poisson models. A total of 2 822 616 women were included, and 42 349 (1.5%) had chronic hypertension and 22 816 were treated during pregnancy. In Poisson models, the adjusted IRR (95% CI) of maternofetal outcomes for women with hypertension were as follows: 1.76 (1.54-2.01) for infant death, 1.73 (1.60-1.87) for small gestational age, 2.14 (1.89-2.43) for preterm birth, 4.58 (4.41-4.75) for preeclampsia, 1.33 (1.27-1.39) for cesarean delivery, 1.84 (1.47-2.31) for venous thromboembolism, 2.62 (1.71-4.01) for stroke or acute coronary syndrome, and 3.54 (2.11-5.93) for maternal death postpartum. In women with chronic hypertension, being treated with an antihypertensive drug during pregnancy was associated with a significantly lower risk of obstetric hemorrhage, stroke, and acute coronary syndrome during pregnancy and postpartum. Conclusions Chronic hypertension is a major risk factor of infant and maternal negative outcomes. In women with chronic hypertension, the risk of pregnancy and postpartum cardiovascular events may be decreased by antihypertensive treatment during pregnancy.