PROSPER: PostpaRtum PrOphylaxiS for PE Randomized Control Trial Pilot

Inclusion Criteria

Women must be at high risk for thromboembolism for one of the following reasons:

• Known low risk thrombophilia (Known = diagnosed prior to enrollment and low risk thrombophilia includes heterozygous factor V Leiden or prothrombin gene variant or protein C deficiency or protein S deficiency. If not previously tested then assumed not to have thrombophilia).
• Immobilization (defined as >90% of waking hours in bed, of a week or more at any point in the antepartum period).

OR any two of the following reasons:

• Postpartum infection (fever (temperature>38.5oC) and clinical signs/symptoms of infection and elevated neutrophil count (higher than local lab normal))
• Postpartum hemorrhage (Estimated blood loss >1000 ml during delivery and postpartum)
• Pre-pregnancy BMI >25 kg/m2
• Emergency cesarean birth (emergency = not planned prior to onset of labour)
• Smoking >5 cigarettes per day prior to pregnancy
• Preeclampsia (blood pressure ≥ 140mmHG systolic and/or ≥90 mmHg diastolic on at least one occasion and proteinuria (1+ on urine dipstick or 300mg/dl or total excretion of 300mg/24 hours) or typical end-organ dysfunction.
• Infant birth weight (adjusted for sex and gestational age) 30U/ml on two measurements a minimum of six weeks apart), persistently positive Anti B2 glycoprotein antibodies (> 20U/ml on two measurements a minimum of six weeks apart), persistently positive lupus anticoagulant (positive on two measurements a minimum of six weeks apart), homozygous factor V Leiden (FVL), homozygous prothrombin gene mutation (PGM), compound heterozygosity factor V Leiden (FVL) and prothrombin gene mutations (PGM), more than 1 thrombophilia (any combination of 2 or more: FVL, PGM, protein C deficiency, protein S deficiency). If not previously tested then assumed not to have thrombophilia).
• Contraindication to heparin therapy, including:
• History of heparin induced thrombocytopenia (HIT)
• Platelet count of less than 80, 000 x 106/L on postpartum Complete Blood Count(CBC)
• Hemoglobin ≤ 75 g/L on postpartum CBC
• Active bleeding at any site (not resolved prior to randomization)
• Excessive postpartum vaginal bleeding (>1 pad per hour prior to randomization).
• Documented gastrointestinal ulcer within 6 weeks prior to randomization
• History of heparin or LMWH allergy
• Severe postpartum hypertension (systolic blood pressure (SBP) > 200mm/hg and/or diastolic blood pressure (DBP) > 120mm/hg)
• Severe hepatic failure (INR >1.8 if liver disease suspected)
• Have received more than one dose of heparin or LMWH since delivery
• < age of legal majority in local jurisdiction (age <18 in Canada)
• Prior participation in PROSPER
• Unable or refused to consent