Preferences of pregnant women for postpartum thromboprophylaxis: the bicentric PREFER-PostPartum study.

Background: Clinical guidelines for postpartum thromboprophylaxis differ due to its uncertain effect and varying preferences of experts. Women's preferences for postpartum thromboprophylaxis are unknown, although they may inform practices and future research.

Objectives: Our aim was to elicit the pregnant women's preferences for postpartum thromboprophylaxis according to different risks of venous thromboembolism (VTE) and bleeding.

Methods: In 2 Swiss and French maternity hospitals, we conducted structured interviews of pregnant or postpartum women. Participants were instructed on pulmonary embolism, deep vein thrombosis, postpartum hemorrhage, and subcutaneous injections of low-molecular-weight heparin (LMWH). First, we randomized women to either standard gamble or time trade-off (2 different validated methods) to estimate the utilities (quality of life, from 0 to 1) of these health states. Second, we elicited the preference for the use of short-term postpartum thromboprophylaxis with LMWH vs none across different risks of postpartum VTE and bleeding through direct-choice exercises.

Results: Among 122 participants, median (IQR) health state utilities were 0.725 (0.30-0.925) for pulmonary embolism, 0.75 (0.40-0.97) for postpartum hemorrhage, 0.85 (0.60-0.97) for deep vein thrombosis, and 0.96 (0.96-0.999) for LMWH injections. The median risk of postpartum VTE for preference of the use of postpartum thromboprophylaxis over no treatment was 0.1% (IQR, 0.01%-0.50%) without LMWH-associated bleeding risk and 0.2% (IQR, 0.1%-5%) with a 1% bleeding risk.

Conclusion: European pregnant women appear to have a high willingness for 10-day postpartum thromboprophylaxis, preferred over no treatment even for low risks of postpartum VTE. This perspective from patients supports the urgent need for a randomized trial evaluating the efficacy and safety of postpartum thromboprophylaxis.