The predictive value of D-dimer test for venous thromboembolism during puerperium in women age 35 or older: a prospective cohort study

Background This study aimed to investigate the predictive value of the D-dimer level for venous thromboembolism (VTE) events during puerperium of women age at 35 years or older, as well as to identify other risk factors associated with the occurrence of VTE. Methods It was a prospective observational cohort study, from January 2014 to December 2018, which involved 12,451 women age 35 or older who delivered at least 28 weeks of gestation at Women’s Hospital of Zhejiang University, School of Medicine. The maternal and fetal demographic characteristics, pregnancy complications, imaging finding and results of laboratory test within postpartum 24 h including D-dimer level, platelet counts and fibrinogen level were collected for analyses. Results 30(2.4‰) women were identified as VTE, including 1 pulmonary embolism event and 29 deep venous thrombosis events. The receiver operating characteristic (ROC) curve analysis suggested the best cutoff point for D-dimer level within postpartum 24 h of women age 35 or older was 5.545 mg/L, with a specificity of 70.0% and a sensitivity of 75.4%. Besides, there was no statistical correlation between platelet counts and VTE, as well as between fibrinogen level and VTE. On multivariate analysis, D-dimer≥5.50 mg/L (OR = 5.874, 95%CI: 2.678–12.886) and emergency cesarean section (OR = 11.965, 95%CI: 2.732–52.401) were independently associated with VTE in puerperium of women age 35 or older. Conclusions We concluded that D-dimer≥5.50 mg/L was an independent predictor of VTE in puerperium with maternal age 35 or older and D-dimer testing was a necessary examination for perinatal women.