For a study, researchers sought to assess trends in and risk factors for venous thromboembolism (VTE) during delivery hospitalizations in the United States.


For the repeated cross-sectional analysis, the National Inpatient Sample from 2000 to 2018 was employed. Venous thromboembolism (including deep vein thrombosis [DVT] and pulmonary embolism) during delivery hospitalizations for women aged 15 to 54 years was determined by year. Joinpoint regression was used to define temporal patterns in VTE, with results provided as the average yearly percent change. Temporal trends in common VTE risk variables were also investigated. The proportion of vaginal and cesarean births with VTE risk factors was assessed by year, and average yearly percent changes with 95% CIs were computed. The link between risk variables and the chance of VTE occurrences was assessed using logistic regression models, both adjusted and unadjusted.


There were 48,546 VTE episodes (6.6/10,000 births) among the 73,109,789 delivery hospitalizations, including 37,312 DVT diagnoses and 12,487 pulmonary embolism diagnoses. Over the research period, rates for vaginal birth hospitalizations increased considerably (average annual percent change 2.5%, 95% CI 1.5–3.5%) but not for cesarean delivery hospitalizations (average annual percent change 0.3%, 95% CI 1.0 to 1.6%). Pulmonary embolism increased after both vaginal and cesarean birth (average yearly percent change 8.7%, 95% CI 6.0–11.5%). Cesarean deliveries with at least one VTE risk factor increased from 27.2% in 2000 to 43.6% in 2018 (average annual percent change 2.6%, 95% CI 2.2–3.1%), while vaginal deliveries increased from 17.7% to 31.4% (average annual percent change 3.4%, 95% CI 2.3–4.4%). VTE diagnoses were found in 5.9% of births with at least two VTE risk factor diagnoses, accounting for 25.4% of all VTE diagnoses. Transfusion (aOR 4.1, 95% CI 3.7–4.5), infection (aOR 5.8, 95% CI 5.3–6.3), history of VTE (aOR 7.2, 95% CI 6.2–8.4), and thrombophilias (aOR 9.6, 95% CI 8.5–11.0) were the factors with the highest VTE risk.


Over the course of the trial, both the risk variables for VTE and the rate of pulmonary embolism rose. Deep vein thrombosis was more common in vaginal birth hospitalizations but not in cesarean delivery hospitalizations.