Background
Phase 3, multicenter, open-label RCT (ALIFE trial). 364 women with a history of ≥2 consecutive miscarriages and hereditary thrombophilia (Factor V Leiden, prothrombin G20210A, protein C/S/antithrombin deficiency, or combined defects) at Dutch hospitals. Enrolled at positive pregnancy test; all had documented thrombophilia. Antiphospholipid syndrome was excluded. This was one of the first adequately powered RCTs in this population.
Interventions and follow up
Arm A: LMWH (nadroparin, prophylactic dose, 2,850 IU anti-Xa daily SC) + aspirin 80 mg daily from positive pregnancy test to 36 week
Arm B: Aspirin 80 mg daily alone
Arm C: Placebo (no LMWH, no aspirin)
Primary endpoint: Live birth rate ≥24 week
mFollow up: Delivery
Arm B: Aspirin 80 mg daily alone
Arm C: Placebo (no LMWH, no aspirin)
Primary endpoint: Live birth rate ≥24 week
mFollow up: Delivery
Results
Live birth rate: 54.8% (LMWH+aspirin) vs 57.4% (aspirin) vs 57.4% (placebo), P=.61 — NS across all comparisons
Miscarriage: ~40–42% across all arms — no difference
Preeclampsia/SGA: Similar across all groups
Miscarriage: ~40–42% across all arms — no difference
Preeclampsia/SGA: Similar across all groups
Adverse events
Main adverse events: LMWH-related: injection-site bruising, minor bleeding. No major thrombotic or hemorrhagic events. Congenital anomalies similar across arms.
Conclusions
Neither LMWH plus aspirin nor aspirin alone improved live birth rates compared to placebo in women with inherited thrombophilia and recurrent miscarriage, refuting the thrombotic hypothesis as the primary mechanism of pregnancy loss in this population.
Key Limitations
Key Limitations: Mixed thrombophilia defects (heterogeneous group) may dilute subgroup-specific effects. Three-arm design led to relatively small numbers per arm for the primary analysis. Women with severe thrombophilia (homozygous FVL, combined defects) were underrepresented. The open-label design and aspirin-vs-placebo comparison are confounded. Timing of intervention (before established fetal cardiac activity) varied.
Clinical Context
ALIFE (2010) and ALIFE2 (2023) together demonstrate no benefit of LMWH in recurrent miscarriage — whether thrombophilia is present or absent. These results directly contradict widespread clinical practice prior to the trials. Current RCOG Green-top Guideline No. 17 and ACOG guidance no longer recommend LMWH for recurrent miscarriage outside of APS or documented VTE. These findings redirected research toward immune and endometrial mechanisms of pregnancy loss.
References