Latency of preterm hypertensive disorders of pregnancy and subsequent cardiovascular complications

Objectives: To test the hypothesis that increasing latency from diagnosis to delivery in patients with preterm hypertensive disorders of pregnancy is associated with an increased maternal risk of cardiovascular admission after delivery. Study design: Retrospective cohort from the IBM MarketScan® Commercial Database from 2006 to 2016. Patients age 15–45 years with a preterm delivery complicated by a hypertensive disorder of pregnancy, at least 6 months of continuous insurance coverage prior to delivery and at least 365 days of coverage post-delivery were included. Main outcome measures: Hospital readmission after delivery for a composite of acute cardiovascular events (cardiomyopathy, heart failure, cardiac arrest, myocardial infarction) or cerebrovascular events. Cox proportional hazards were used to estimate the risk of the primary outcome for each week of latency from diagnosis to delivery. Results: There were 34,989 women in the study with a median follow-up of 2.57 years (IQR 1.66 to 1.54 years) with a median time from diagnosis to delivery of three days (IQR 0 to 14 days). An increasing time from diagnosis to delivery was associated with an increased risk of an acute cardiovascular event (adjusted HR 1.06, 95% CI 1.01, 1.11 per week), in models adjusted for maternal comorbidities and demographic factors. Later gestational age at diagnosis was associated with a decreased risk of maternal cardiovascular admission after delivery (aHR 0.94, 95% CI 0.91, 0.98 for each week increase in gestational age). Conclusions: Prolonging expectant management of preterm hypertensive disorders of pregnancy is associated with an increased risk of maternal cardiovascular disease after delivery.