540 Effect of timely treatment of acute severe intrapartum hypertension on risk of severe maternal morbidity

Abstract

Hypertensive disorders of pregnancy (HDP) are among the leading causes of maternal mortality and severe maternal morbidity (SMM) worldwide. Studies have demonstrated an elevated risk of SMM in those with HDP who develop severe intrapartum hypertension (SIH), as well as a decreased risk of SMM with timely treatment of SIH. Our study sought to evaluate if the development of SIH was associated with SMM among patients at an urban safety net hospital and if timely treatment of SIH was associated with a reduction in SMM within this same population. Population cohort study of deliveries at a single urban safety net hospital in Atlanta, Georgia between 2016 and 2018. Among deliveries with HDP, we identified those with persistent SIH (>160/105 mmHg) and further classified women as having received timely (within 60 minutes) or delayed treatment. We used Fisher’s exact test and multivariable robust Poisson regression to compare SMM risk for women with SIH according to timing of treatment. Of the 3,723 deliveries within the study timeframe, 1,204 (32.0%) had HDP without SIH and 211 (0.6%) had HDP with SIH. Among deliveries with SIH, 49.0% received timely treatment. An SMM event complicated 27.0% of deliveries with SIH. Of those who received timely treatment, 23.3% experienced an SMM event compared to 30.6% of patients who received delayed treatment. After controlling for age, race, insurance status, prenatal care utilization, and multiple gestations, the adjusted risk ratio was 0.72 (CI 0.44-1.16). Comparison of specific SMM events between groups showed that timely treatment of SIH was associated with a statistically significant decrease in risk of acute renal failure (aRR 0.40, CI 0.15-1.05). Patients with HDP diagnoses are at an increased risk of SMM overall, with those with SIH at greatest risk of SMM. Within our patient population, timely treatment of SIH was associated with specific reduction in risk of acute renal failure, as well as a reduction in overall risk of SMM. These findings support efforts to expedite treatment of SIH.