Risk factors for recurrence during a pregnancy following a first venous thromboembolism: A French observational study

Abstract

Background: Women with a previous venous thromboembolism (VTE) are at risk of recurrence during pregnancy. Objectives: We aimed to assess the incidence rate of recurrent VTE during pregnancy, according to the period of pregnancy, and the clinical parameters associated with recurrence, in a prospective cohort of women of childbearing age after a first VTE. Patients/Methods: A total of 189 women aged 15–49 years with a first documented VTE were followed until a subsequent pregnancy of at least 20 weeks’ gestation between 2000 and 2020. VTE recurrences during pregnancy were recorded, as were potential clinical risk factors for recurrence. Results: Recurrent VTE occurred in six women during antepartum: five during the first trimester (incidence rate 106.4 per 1000 women-years) (95% confidence interval [CI] 46.3–226.0); none during the second trimester; and one during the third trimester (incidence rate 27.0 per 1000 women-years [95% CI 4.8–138.2]). During postpartum, recurrences occurred in 11 women (incidence rate 212.8 per 1000 women-years [95% CI 119.9–349.1]). These 17 recurrent VTEs presented as pulmonary embolism ± deep vein thrombosis (DVT) in five patients and isolated DVT in 12. Failure of thromboprophylaxis occurred in two cases (33.3%) antepartum and in 10 cases (90.9%) postpartum. In multivariable analysis, only obesity (defined on prepregnancy body mass index) was associated with recurrent VTE (odds ratio 3.34 [95% CI 1.11–10.05, p =.03]). Conclusions: This study confirms a high risk of recurrent VTE postpartum, despite thromboprophylaxis, in women with a previous VTE. Only obesity was associated with VTE recurrence during pregnancy, suggesting that low-dose anticoagulation might not be appropriate in obese pregnant women.