The use of low-molecular-weight heparin (LMWH) did not improve rates of live births for women with inherited thrombophilia and recurrent pregnancy loss, according to results of a recent study. The study’s findings were reported in the Lancet.

The open-label ALIFE2 trial (EudraCT Identifier: 2015-002357-35) was conducted at hospitals in the UK, Netherlands, USA, Belgium, and Slovenia. It included women aged 18 to 42 years who had inherited thrombophilia and a history of 2 or more pregnancy losses.

Patients were randomly assigned 1:1 to be treated, after a positive urine pregnancy test, with either low-dose LMWH (LMWH group) or no LMWH (control group). Both groups also received standard care. In patients receiving LMWH, it was begun by 7 weeks of gestation at the latest and was given until completion of pregnancy. The livebirth rate was the primary study outcome, and safety outcomes were also assessed.

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There were 326 women included in the analysis, with 164 assigned to the LMWH group and 162 to the control group. Participants had median ages of 34 years in the LWMH group and 33 years in the control group, and 36% of participants in each group had an age above 36 years. There were data available for analysis of the primary outcome in 162 women in the LMWH group and 158 women of the control group.

Among these women, live births occurred with 116 (72%) in the LMWH group, compared with 112 (71%) women of the control group (absolute risk difference, 0.7%; 95% CI, -9.2% to 10.6%; adjusted odds ratio; 1.08; 95% CI, 0.65-1.78; P =.77).

Within the full study population, adverse events were reported with 24% of women of the LMWH group and in 23% of women of the control group. The groups did not show differences in rates of reported bleeding complications, and heparin-induced thrombocytopenia was not observed. Serious adverse events considered related to study medication also were not observed. In the LMWH group, 45% of women reported experiencing easy bruising, compared with 10% in the control group.

The study investigators concluded that the trial showed no significant difference in livebirth rates between treatment groups in this study population. “Based on our findings, we advise against the use of LMWH in women with recurrent pregnancy loss and confirmed inherited thrombophilia,” they wrote in their report.

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, or device companies. Please see the original reference for a full list of disclosures.


Quenby S, Booth K, Hiller L, et al; for the ALIFE2 Block Writing Committee and ALIFE2 Investigators. Heparin for women with recurrent miscarriage and inherited thrombophilia (ALIFE2): an international open-label, randomised controlled trial. Lancet. Published online June 1, 2023. doi:10.1016/S0140-6736(23)00693-1