Association between peripartum hysterectomy and venous thromboembolism

BACKGROUND: The risk of venous thromboembolism after delivery is modified by mode of delivery, with the risk of venous thromboembolism being higher after cesarean delivery than vaginal delivery. The risk of venous thromboembolism after peripartum hysterectomy is largely unknown. OBJECTIVE: This study aimed to compare the incidence and risk of venous thromboembolism among women who had and did not have a peripartum hysterectomy. Furthermore, we sought to compare the risk of venous thromboembolism after hysterectomy with other patient, pregnancy, and delivery risk factors known to be associated with venous thromboembolism. STUDY DESIGN: This was a cross-sectional study of women with delivery encounters identified in the Nationwide Readmissions Database from October 2015 to December 2017. Delivery encounters and all variables of interest were identified using the International Classification of Diseases, Tenth Revision diagnosis and procedure codes. The incidence of venous thromboembolism during delivery and rehospitalizations within 6 weeks after discharge was compared among women who had and did not have a peripartum hysterectomy. Multivariable logistic regressions were used to estimate associations between venous thromboembolism and hysterectomy, adjusted for the following characteristics: maternal age, payer at time of delivery, obesity, hypertension, diabetes mellitus, tobacco use, multifetal gestation, peripartum infection, and peripartum hemorrhage. Similarly, venous thromboembolism risk was compared by mode of delivery, including hysterectomy. Diagnoses that may have been indications for peripartum hysterectomy were identified among patients who underwent a hysterectomy and compared between those who did and did not have venous thromboembolism. Analyses used survey weights to obtain population estimates. RESULTS: Of the 4,419,037 women with deliveries, 5098 (11.5 per 10,000 deliveries) underwent a hysterectomy. Moreover, 110 patients (215.8 per 10,000 deliveries) were diagnosed with venous thromboembolism after hysterectomy. The risk of venous thromboembolism was significantly higher in women who underwent a hysterectomy than in women who did not have a hysterectomy (unadjusted odds ratio, 25.1 [95% confidence interval, 20.0-31.5]; adjusted odds ratio, 11.2 [95% confidence interval, 8.7-14.5]; P<.001). Comparing the risk of venous thromboembolism by mode of delivery, the unadjusted and adjusted incidences of venous thromboembolism were 6.9 (95% confidence interval, 6.5-7.3) and 7.4 (95% confidence interval, 6.9-7.8) per 10,000 deliveries among women after vaginal delivery without peripartum hysterectomy, 12.5 (95% confidence interval, 11.8-13.1) and 11.3 (95% confidence interval, 10.7-12.0) per 10,000 deliveries after cesarean delivery without hysterectomy; and 217.2 (95% confidence interval, 169.1-265.2) and 96.9 (95% confidence interval 76.9-126.5) per 10,000 deliveries after hysterectomy, regardless of mode of delivery. Of the 110 diagnoses of venous thromboembolism with peripartum hysterectomy, 89 (81%) occurred during delivery admission. Of the remaining 21 cases, 50% occurred within the first 10 days after discharge from delivery, and 75% occurred within 25 days after discharge. CONCLUSION: These findings have demonstrated that peripartum hysterectomy is associated with a markedly increased risk of venous thromboembolism in the postpartum period, even when controlling for other known risk factors for postpartum thromboembolic events. Here, the incidence of venous thromboembolism after peripartum hysterectomy (2.2%) met some guideline-based risk thresholds for routine thromboprophylaxis, potentially for at least 2 weeks after delivery. Further investigation into the role of routine venous thromboembolism prophylaxis during and after delivery is needed.