Use of low molecular weight heparins for the preventing placenta-associated complications: a systematic review and meta-analysis

Aim: to evaluate the effectiveness of low-molecular-weight heparins (LMWHs) in preventing placenta-associated complications (РАС), such as preeclampsia (PE), fetal growth restriction (FGR), intrauterine fetal death (IUFD) and placental abruption (PА), in women at high risk for these complications but without thrombophilia or thromboembolic disorders, based on a review and meta-analysis of publications released within the last twenty years.

Materials and Methods. A search for relevant randomized controlled trials was conducted in electronic databases (PubMed/MEDLINE, Embase, Web of Science, etc.) spanning from 2005 to 2025. The meta-analysis included 11 trials involving a total of 1965 women. PE, FGR, IUFD, and PA were considered as the primary outcomesFixed-effects models were used for analysis, and the results were presented as risk ratios with 95 % confidence intervals.

Results. LMWHs use was associated with a reduced IUFD risk (0.77 [0.65; 0.90]; p = 0.001), PA (0.67 [0.52; 0.86]; p = 0.002), and PE occurrence (0.74 [0.62; 0.89]; p = 0.001). No significant effect of LMWHs use on FGR risk was found (0.93 [0.69; 1.25]; p = 0.62). Considerable heterogeneity (I² > 60 %) was observed while analyzing IUFD, PE and PA. Funnel plot assessment did not rule out a potential risk of publication bias and requires further investigation.

Conclusion. Prophylactic LMWHs use in women at high risk for РАС without thrombophilia may reduce the incidence of complications such as PE, IUFD, and PA. These findings indicate the need for multicenter studies with detailed analyses to identify patient cohorts where prophylactic LMWHs use for complication prevention provides a clear clinical and pathogenetic rationale.

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