Metabolic Syndrome in the Etiopathogenesis of Recurrent Pregnancy Loss: A Systematic Review

Abstract

Recurrent pregnancy loss (RPL) often remains unexplained even after routine evaluation, which makes potentially modifiable risk factors especially important. Metabolic syndrome (MetS) has gained attention in this context because it combines central obesity, insulin resistance or dysglycemia, hypertension, and atherogenic dyslipidemia into a single adverse reproductive phenotype. This systematic review summarizes current evidence on the role of MetS in the etiopathogenesis of RPL. The available literature suggests that women with RPL more often demonstrate metabolic abnormalities, higher body mass index, oxidative stress, and immune-inflammatory imbalance. Among the most consistent findings are increased malondialdehyde (MDA), reflecting enhanced lipid peroxidation, and a shift toward a pro-inflammatory cytokine profile, commonly characterized by higher interleukin-6 (IL-6), lower or relatively insufficient interleukin-10 (IL-10), and an increased IL-6/IL-10 ratio. Taken together, these data support the idea that MetS creates a biologically unfavorable background for implantation, placentation, and early fetal development. Despite heterogeneity across studies, metabolic assessment before conception appears clinically relevant in women with RPL.