Role of Low Molecular Weight Heparin in Unexplained Recurrent Pregnancy Loss.

Objective: To evaluate the effectiveness of low molecular weight heparin (LMWH) in unexplained recurrent pregnancy loss (URPL).

Study design: Open-labelled, single-centre, randomised controlled trial. Place and Duration of the Study: Department of Obstetrics and Gynaecology, DG Khan Hospital, Dera Ghazi Khan, Pakistan, from June 2023 to December 2024.

Methodology: One hundred and seventy pregnant women aged 18-44 years with a gestational age exceeding 8 weeks and a history of three or more consecutive first-trimester pregnancy losses were randomly assigned to one of two groups using the sealed envelope lottery method. The LMWH group (n = 85) received a daily subcutaneous injection of 40 mg LMWH, while the placebo group (n = 85) was given a multivitamin tablet as a placebo. The primary outcome was assessed in terms of efficacy, defined as live births occurring after reaching 24 weeks of gestation. Secondary outcomes included both maternal and foetal health outcomes. Numeric data were compared by applying the Mann-Whitney U test, while categorical data were compared by employing the Chi-square test. For all inferential statistics, a value of p <0.05 was considered statistically significant.

Results: In a total of 170 women, the median age was 32.00 (30.00-35.00) years. In the LMWH group, the proportion of live-births was 88.0% versus 73.4% in the placebo group (p = 0.019). It was found that the proportion of caesarean section was significantly higher among women of the LMWH group (72.6% vs. 51.7%, p = 0.014). The proportion of premature birth was significantly high in placebo group (25.9% vs. 9.6%, p = 0.013).

Conclusion: This study demonstrates that the LMWH is associated with a significantly higher live birth rate in women with RPL, without increasing the risk of adverse maternal and neonatal outcomes.

Key words: Heparin, Gestational age, Low birth weight, Placebo, Pregnancy loss.