Identifying Thromboprophylaxis and Aspirin Use in Pregnancy: Predictors and Maternal Outcomes-the Italian MoMs Study

The use of low-molecular-weight heparin (LMWH) and aspirin during pregnancy is increasing, yet robust clinical trial evidence supporting their efficacy remains limited.In a multicenter prospectively enrolled cohort study, we evaluated the prescription patterns and associated maternal-fetal outcomes of antithrombotic therapy in 2,622 women admitted for delivery across three Italian obstetric centers between January 2022 and November 2023. Data were collected on conception methods, administration details (timing, dose, indication) of LMWH and low-dose aspirin (LDA), and maternal-fetal outcomes from admission to postpartum discharge. Data on prescription of antithrombotic drugs were available for 1,898 women.Among 1,898 women with available data, 157 (8.3%) received LDA (100 mg/day) and 746 (39.3%) received LMWH (49 during pregnancy and 697 in the postpartum period). Predictors of LMWH use included prior cesarean (OR 3.1, 95% CI 1.7-5.8), preterm delivery (OR 3.8, 95% CI 1.7-8.9), pregnancy loss (OR 2.7, 95% CI 1.5-4.9), and assisted conception (OR 14.6, 95% CI 2.8-76.5). LDA use was associated with pregnancy loss (OR 2.1, 95% CI 1.4-3.0), ART (OR 4.7, 95% CI 2.2-10.2), and LMWH co-administration (OR 2.5, 95% CI 1.1-5.5). Postpartum LMWH use was primarily associated with cesarean delivery. Postpartum hemorrhage occurred in 2.4% of cases, with no significant difference in those receiving LDA or LMWH.These findings reflect current real-world prescribing practices and highlight key maternal characteristics influencing antithrombotic therapy decisions. The study underscores the importance of evidence-based approaches in the use of LMWH and LDA during pregnancy, particularly in high-risk populations, to improve maternal-fetal outcomes while minimizing unnecessary exposure to therapies with uncertain benefit.