Chronic Hypertension in Pregnancy and Placenta-Mediated Complications Regardless of Preeclampsia.

Background: The prevalence of chronic hypertension in women of reproductive age is on the rise mainly due to delayed childbearing. Maternal chronic hypertension, prevailing prior to conception or manifesting within the early gestational period, poses a substantial risk for the development of preeclampsia with adverse maternal and fetal outcomes, specifically as a result of placental dysfunction. We aimed to investigate whether chronic hypertension is associated with placenta-mediated complications regardless of the development of preeclampsia in pregnancy.

Methods: This was a population-based, retrospective cohort study from 'Soroka' university medical center (SUMC) in Israel, of women who gave birth between 1991 and 2021, comparing placenta-mediated complications (including fetal growth restriction (FGR), placental abruption, preterm delivery, and perinatal mortality) in women with and without chronic hypertension. Generalized estimating equation (GEE) models were used for each outcome to control for possible confounding factors.

Results: A total of 356,356 deliveries met the study's inclusion criteria. Of them, 3949 (1.1%) deliveries were of mothers with chronic hypertension. Women with chronic hypertension had significantly higher rates of all placenta-mediated complications investigated in this study. The GEE models adjusting for preeclampsia and other confounding factors affirmed that chronic hypertension is independently associated with all the studied placental complications except placental abruption.

Conclusions: Chronic hypertension in pregnancy is associated with placenta-mediated complications, regardless of preeclampsia. Therefore, early diagnosis of chronic hypertension is warranted in order to provide adequate pregnancy follow-up and close monitoring for placental complications, especially in an era of advanced maternal age.