Trends in Antepartum, Delivery, and Postpartum Venous Thromboembolism

OBJECTIVE:To assess trends in risk for obstetric venous thromboembolism (VTE).METHODS:This retrospective cohort study analyzed data from the 2008-2019 Merative MarketScan Commercial Claims and Encounters and Medicaid Multi-State databases. Women aged 15-54 years with a delivery hospitalization and health care enrollment from 1 year before pregnancy to 60 days after delivery were identified. Risk for VTE during pregnancy from 2009 to 2019 was analyzed with joinpoint regression, with trends reported as the average annual percent change (APC). Venous thromboembolism events were identified with diagnosis codes along with pharmacy receipt of anticoagulants. Additionally, the association between risk factors for VTE and VTE events was evaluated with log-Poisson regression models with unadjusted and adjusted risk ratios (aRR) with 95% CIs as measures of association.RESULTS:Among 1,970,971 pregnancies, there were 5,270 VTE events, of which 35.5% (n=1,871) included a pulmonary embolism diagnosis and 64.5% (3,399) included a deep vein thrombosis diagnosis, alone. Risk for VTE increased significantly during pregnancy over the study period, with an APC of 9.2% (95% CI, 5.7-12.9%). Rates of VTE also increased individually during the antenatal period (APC 8.2%, 95% CI, 3.7-12.9%), during delivery hospitalizations (APC 12.2%, 95% CI, 7.4-17.3%), during the postpartum period (APC 8.4%, 95% CI, 5.9-11.0%), and individually for vaginal and cesarean delivery hospitalizations. Trends analyses individually for pulmonary embolism (APC 12.4%, 95% CI, 8.6-16.4%) and deep vein thrombosis (APC 7.6%, 95% CI, 4.0-11.3%) also demonstrated significant increases. In adjusted analyses for VTE, obesity (aRR 1.91, 95% CI, 1.78-2.05), chronic heart disease (aRR 3.14, 95% CI, 2.93-3.37), tobacco use (aRR 1.61, 95% CI, 1.34-1.95), asthma (aRR 1.46, 95% CI, 1.33-1.60), and preeclampsia (aRR 1.44, 95% CI, 1.31-1.58) were the factors associated the greatest increased adjusted relative risk.CONCLUSION:Risk for obstetric VTE increased significantly over the study period. Risk increased during the antenatal, delivery, and postpartum periods and for both cesarean and vaginal delivery.