452: Re-defining chronic hypertension in pregnancy

Abstract

The American Heart Association recently endorsed guidelines that lower the diagnostic criteria for chronic hypertension outside of pregnancy to ≥ 130/80 mm Hg. We investigated the relationship between blood pressure (BP) during the first half of pregnancy and maternal-fetal outcomes. We hypothesized that using the same lower diagnostic threshold of BP ≥ 130/80 mm Hg prior to 20 weeks gestation would identify women at increased risk for adverse maternal and fetal outcomes compared with normotensive controls. We conducted a retrospective cohort study of women with singleton pregnancies who received prenatal care and delivered at a single tertiary care center from 2010-2017. Women were categorized into three distinct groups based on their BP status. Group 1: Women with chronic hypertension based on current ACOG guidelines (existing diagnosis of chronic hypertension or BP ≥ 140/90 mm Hg prior to 20 weeks gestation). Group 2: Women with no pre-pregnancy diagnosis of hypertension, but with systolic BP ≥ 130 mm Hg or diastolic BP ≥ 80 mm Hg on two occasions prior to 20 weeks gestation. Group 3: Normotensive controls. Maternal and fetal outcomes were collected and compared between groups. The primary outcome was development of preeclampsia. One- way ANOVA was used to compare groups for continuous outcomes and logistic regression analyses were used to compare groups for categorical outcomes. Of the 3,761 women that met criteria for study entry, 134 were found to have chronic hypertension based on current guidelines (group 1), 327 had BP ≥ 130/80 mm Hg prior to 20 weeks gestation (group 2), and 3300 were normotensive controls (group 3). Women in groups 1 and 2 had similar demographic characteristics. (Table 1). They were more likely to be older, have a higher prepregnancy BMI, and have pregestational diabetes. 25.4% of women in group 1 and 15% of women in group 2 developed preeclampsia as compared to 4.8% of controls (p<0.001). Women in group 2 were also more likely to develop gestational hypertension, gestational diabetes, deliver preterm, and undergo cesarean delivery than were controls. (Table 2). Women with BP ≥ 130/80 mm Hg prior to 20 weeks gestation are at increased risk for developing hypertensive disorders of pregnancy. Additional analyses will clarify if blood pressure prior to 20 weeks gestation is an independent predictor of preeclampsia.View Large Image Figure ViewerDownload Hi-res image Download (PPT)