Mild chronic hypertension in pregnancy: To treat or not to treat?
Dr Lockwood, Editor-in-Chief, is Dean of the Morsani College of Medicine and Senior Vice President of USF Health, University of South Florida, Tampa.
Chronic hypertension in pregnant women continues to increase in the United States, most likely because of delayed childbearing and the obesity epidemic. Twenty years ago chronic hypertension complicated less than 1% of gestations. In the period 2007–2008 this rate grew to 1.5%, with the rate accelerating after 2001.1 Pregnancy outcomes of such pregnancies are, of course, concerning.
A recent secondary analysis of 759 women with chronic hypertension diagnosed before 20 weeks’ gestation and enrolled in the NICHD Maternal-Fetal Medicine Units Network’s high-risk aspirin preeclampsia prevention trial suggests just how concerning.2 The authors divided these women into 3 categories based on pre-enrollment blood pressures: < 140/90, 140–150/90-99, and 151–159/100–109 mmHg.
The primary composite outcome, which included perinatal death, severe preeclampsia, placental abruption, and indicated preterm birth < 35 weeks, occurred in 10.7%, 19.0%, and 30% of these women, respectively. The occurrence of small-for-gestational-age (SGA) infants also increased in each category: 8.8%, 12.3%, and 23.7%, respectively, as did superimposed preeclampsia (21.1%, 29.9%, and 41.7%) and perinatal death (3.1%, 7.2%, and 10.0%).
Interestingly, in this study significantly more women whose initial blood pressures were < 140/90 mmHg at enrollment had started antihypertensive therapy before pregnancy than those in the 140–150/90–99 and 151–159/100–109 mmHg pre-enrollment blood pressure categories (72.6% vs 55.2% and 48.3%, respectively, P < 0.001). These findings led the authors to speculate that better control of blood pressure among pregnant patients with mild chronic hypertension could improve outcomes.