(679) American Heart Association (AHA) Stage 1 Hypertension and Perinatal Outcomes by Gestational Age at Delivery

Retrospective cohort of patients receiving prenatal care and delivering ≥37 weeks’ GA at a single tertiary center (2013-2018). All included patients had ≥2 BPs measured < 20weeks GA. Patients with known chronic HTN (BP≥140/90 or anti-HTN use) were excluded. Primary exposure was stage 1 HTN (vs no stage 1 HTN: normal BP < 130/80). Primary outcomes were adverse maternal and neonatal composites (Table 1). Multivariable generalized linear regression models compared delivery outcomes between patients with normal BP and stage 1 HTN stratified by GA. Breslow-Day tests for homogeneity were performed across GA strata.


Results: Of 15929 included patients, 2118(13.3%) had stage 1 HTN. In the entire cohort, mean maternal age and BMI were 27.4±5.9yrs and 29.2±7.9kg/sqm; 1546(9.7%) had comorbidities. Patients with stage 1 HTN (vs. normal BP) were more likely to be older, Black, labor spontaneously and have comorbidities. The primary maternal and neonatal composites occurred in 3015(18.9%) and 4537(28.5%) patients, respectively, and were more prevalent at earlier GAs. Patients with stage 1 HTN (vs. normal BP) had higher odds of the primary maternal composite in the 37w0d-38w6d and ≥40w groups. However, tests of homogeneity across GA strata were not significant. There was no difference in the primary neonatal composite. Stage 1 HTN was associated with lower odds of NICU admission among deliveries at 39w0d-39w6d, which differed from other delivery GA (Table 2; p< 0.05).

Conclusion: Stage 1 HTN is associated with higher odds of maternal morbidity regardless of GA. The association between stage 1 HTN and NICU admission differed by delivery GA with lower odds of NICU admission among deliveries at 39w. Randomized trials are needed to explore these findings.