A comparison of international clinical practice guidelines for postpartum venous thromboembolism prophylaxis

Venous thromboembolism is a leading cause of maternal death worldwide. The postpartum period is a time of particularly increased risk. International guidelines provide recommendations for when a woman should be offered thromboembolism prophylaxis, however they differ greatly in their criteria as to which women qualify for low molecular weight heparin (LMWH). The aim of this study was to determine the most common risk factors for women being recommended LMWH and compare the proportion of women who would qualify for postpartum LMWH according to four international guidelines.

This cross-sectional study evaluated rates of postpartum LMWH prophylaxis by applying guideline recommendations from the American College of Chest Physicians (ACCP), the Royal College of Obstetricians and Gynaecologists (RCOG), the Society of Obstetricians and Gynaecologists of Canada (SOGC) and the Society of Obstetric Medicine of Australia and New Zealand (SOMANZ). Demographic, medical and obstetric risk factors for venous thromboembolism were identified for individual women from one regional and two tertiary maternity hospitals in New South Wales, Australia between February and October 2022.

A total of 338 women were included in the analyses. By applying RCOG guidelines, 53.6% of women would have qualified for postpartum LMWH compared with 40.2% of women using SOMANZ guidelines, 37.3% using SOGC guidelines, and 8.3% using ACCP guidelines. The most common risk factors were caesarean birth, maternal age greater than 35 years, body mass index above 30 kg/m² and instrumental birth.

There are considerable differences in the rates of women receiving postpartum pharmacological venous thromboembolism prophylaxis when recommendations from different international guidelines are applied. These differences reflect the wide variation in guideline recommendations for the use of LMWH following birth.