Re-evaluating low-molecular-weight heparin use in recurrent missed miscarriage: current evidence and future...

Area of Science:

• Reproductive Medicine
• Hematology
• Obstetrics

Background:

• Recurrent missed miscarriage (RMM) is a heterogeneous and distressing condition.
• Low-molecular-weight heparin (LMWH) combined with low-dose aspirin improves live-birth rates in obstetric antiphospholipid syndrome (APS).
• The efficacy and optimal dosing of LMWH in APS-negative RMM remain uncertain.

Purpose of the Study:

• To synthesize evidence on the use of LMWH in recurrent missed miscarriage (RMM).
• To evaluate live-birth outcomes, trial limitations, pharmacokinetics, and safety of LMWH regimens.
• To identify knowledge gaps for future research in APS-negative RMM.

Main Methods:

• Narrative synthesis of randomized controlled trials (ALIFE, ALIFE2), systematic reviews, and pharmacokinetic studies.
• Analysis of national and international guidelines (RCOG, ESHRE).
• Focus on live-birth rates, trial design, pharmacokinetic data (once-daily vs. twice-daily dosing), and safety.

Main Results:

• Strong evidence supports LMWH plus aspirin for live-birth rates in women with APS.
• In APS-negative RMM, randomized trials and meta-analyses show no consistent live-birth benefit.
• Clinical heterogeneity, underpowering, and inclusion of chromosomally abnormal losses limit interpretation; trials predominantly used once-daily LMWH.

Conclusions:

• Routine LMWH for APS-negative RMM is not recommended outside of clinical trials.
• Further research is needed on genetic stratification, direct comparison of LMWH dosing frequencies (once-daily vs. twice-daily), and patient-centered outcomes.
• Well-designed, powered trials with genetic/phenotypic enrichment and pharmacokinetic sub-studies are required to resolve clinical equipoise.