Nationwide Analysis of Maternal Mortality Due to Venous Thromboembolism.

OBJECTIVE

To describe the clinical profile, management, and potential preventability of maternal deaths from venous thromboembolism (VTE) based on data from the French maternal mortality surveillance system.

METHODS

We conducted a retrospective descriptive study of all maternal deaths that resulted from a VTE event in France from 2007 to 2018. Deaths were identified through the nationwide permanent enhanced maternal mortality surveillance system-ENCMM (Enquête Nationale Confidentielle sur les Morts Maternelles [French National Confidential Enquiry into Maternal Deaths]). Women were considered for two groups based on the time of VTE onset, antepartum or postpartum. Maternal characteristics, clinical features, and preventability factors were described for these two groups.

RESULTS

During the 12-year study period, 99 women died from VTE, and the corresponding maternal mortality ratio remained stable, at around 1.0 per 100,000 live births. Analyses were conducted on 80 maternal deaths that resulted from antepartum (n=37, 46.2%) and postpartum (n=43, 53.8%) VTE with available data from confidential inquiry. Risk factors were found in 67.6% (25/37) of antepartum cases and 93.0% (40/43) of postpartum cases. Most women (62.5%) only had moderate risk factors, most often multiple (two or more, 66.7%). Among women who died from postpartum VTE, 37.2% (16/43) had acquired risk factors resulting from obstetric conditions (postpartum hemorrhage or preeclampsia). Overall, 46.2% of VTE-related maternal deaths were considered preventable and this proportion did not significantly change over time. According to national guidelines, thromboprophylaxis was indicated in 30 of 80 (37.5%) women who died from antepartum and postpartum VTE (two in the antepartum period, 5.4%; 28 in the postpartum period, 65.1%). Of these women, 13 (43.3%) did not receive thromboprophylaxis and eight (26.7%) received an inappropriate dose or duration of thromboprophylaxis.

CONCLUSION

Nearly half of VTE-related maternal deaths were preventable. Women who died had a high prevalence of cumulative moderate VTE risk factors as well as acquired factors related to obstetric complications. This underlines the importance of repeated assessment along pregnancy to integrate the evolutionary nature of VTE risk in the obstetric population and improve the quality of care.