The Association of Hypertensive Disorders of Pregnancy with Infant Mortality, Preterm Delivery, and Small for Gestational Age

Gestational hypertension, preeclampsia, eclampsia, and chronic hypertension (CHTN) are associated with adverse infant outcomes and disproportionately affect minoritized race/ethnicity groups. We evaluated the relationships between hypertensive disorders of pregnancy (HDP) and/or CHTN with infant mortality, preterm delivery (PTD), and small for gestational age (SGA) in a statewide cohort with a diverse racial/ethnic population. All live, singleton deliveries in South Carolina (2004-2016) to mothers aged 12-49 were evaluated for adverse outcomes: infant mortality, PTD (20 to less than <37 weeks) and SGA (<10th birthweight-for-gestational-age percentile). Logistic regression models adjusted for sociodemographic, behavioral, and clinical characteristics. In 666,905 deliveries, mothers had superimposed preeclampsia (HDP + CHTN; 1.0%), HDP alone (8.0%), CHTN alone (1.8%), or no hypertension (89.1%). Infant mortality risk was significantly higher in deliveries to women with superimposed preeclampsia, HDP, and CHTN compared with no hypertension (relative risk [RR] = 1.79, 1.39, and 1.48, respectively). After accounting for differing risk by race/ethnicity, deliveries to women with HDP and/or CHTN were more likely to result in PTD (RRs ranged from 3.14 to 5.25) or SGA (RRs ranged from 1.67 to 3.64). As CHTN, HDP and superimposed preeclampsia confer higher risk of adverse outcomes, prevention efforts should involve encouraging and supporting mothers in mitigating modifiable cardiovascular risk factors.