PROSPER: PostpaRtum PrOphylaxiS for PE Randomized Control Trial Pilot

The PROPSER pilot is a randomized, open-label pilot study comparing prophylactic low molecular weight heparin (LMWH) to saline placebo. The PROSPER pilot study will assess the feasibility of conducting a full trial as measured by the number of subjects recruited per center per month. In addition, clinical data will be collected to determine an estimate of the primary outcome event rate (symptomatic VTE or asymptomatic proximal deep vein thrombosis (DVT) and major bleeding event rate for the full trial in LMWH and control groups. If our pilot results indicate that no substantial changes are needed to the study design, we will include the pilot data in the primary and secondary outcome analyses for the full trial (i.e. a "Vanguard trial" or internal pilot trial). Eligible consenting women at risk of postpartum thrombosis will be randomized within 36 hours after delivery of the placenta and will be equally allocated to 2 trial arms, either the treatment group: prophylactic-dose LMWH, subcutaneously once daily for 10 days (+/-3 days), or the control group. At 10 days (+/- 3 days), all women will have a study visit to assess for study outcomes, including bilateral leg ultrasound screening for VTE and a D-dimer test. A final telephone follow-up will occur at 90 days for outcome assessment of subsequent VTE, bleeding or other adverse events.