Venous thromboembolism (VTE) is currently the second cause of death in women of reproductive age worldwide. The incidence of VTE during pregnancy is 1.2 to 1.4/1000 women, half of VTE occurring during postpartum and as PE in majority of cases, accounting for 8.8% of maternal deaths.

Majority of postpartum VTE occurs in women with one or more moderate risk factors (obesity, caesarean section, postpartum hemorrhage). For these women at intermediate risk, the efficacy and safety of thromboprophylaxis have not been assessed yet during postpartum and international guidelines for pharmacological thromboprophylaxis, based on data extrapolated from other populations, observational studies and small clinical trials are inconsistent across countries.

We designed an open-label, randomized, controlled trial, aiming to demonstrate the superiority of a pharmacological thromboprophylaxis strategy with LMWH (LMWH type chosen according to physician / patient's preference) during 6 weeks after delivery (the 6-weeks follow-up visit being matched with usual care) in women at intermediate risk, over no pharmacological thromboprophylaxis.

Inclusion Criteria:

• Women at intermediate risk of VTE during post-partum= with a 3% or more risk of VTE based on a validated prediction model* or International guidelines (ACCP 2012).

• Age over 18 years

• Delivery between 6 hours and < 36 hours

• Written informed consent

  • Definition: Intermediate risk is defined as ≥ 3%, based on risk prediction model developed by Sultan et al taking in account: smoking, varicose veins, obesity, comorbidities, diabetes, pre-eclampsia, post-partum hemorrhage, postpartum infection, emergency or elective section or following ACCP guidelines: one major risk factor or two minor risk factors.

Exclusion Criteria:

• Previous personal history of VTE
• LMWH started during antenatal period
• Need for anticoagulation at curative dose
• Contraindication to LMWH (previous heparin induced thrombopenia, hemostatic impairment, known severe renal insufficiency)
• Women who received more than two doses of LMWH since delivery
• Unable or refusal to give informed consent
• Aspirin at a daily dose 100 mg or dual antiplatelet therapy
• Previous inclusion in Mum-VTE study
• Concomitant participation in another therapeutic study

All collected data that underlie results in a publication

Data will be available beginning five years and ending fifteen years following the final study report completion

Data access requests will be reviewed by the internal committee of Brest UH. Requestors will be required to sign and complete a data access agreement.

All critical events (VTE, bleeding and mortality) will be validated by a central, independent clinical events committee (ICEC) which will adjudicate outcomes blinded for treatment allocation (PROBE study).