Environmental Exposure-Induced Epigenetic Modifications and Adverse Pregnancy Outcomes: A Systematic Review.

Prenatal environmental exposures may alter epigenetic regulation, influencing fetal development and pregnancy outcomes. The aim of the study was to systematically review original studies examining associations between environmental exposures, epigenetic modifications, and pregnancy-related disorders. A systematic search of PubMed, ScienceDirect, Cochrane Library, and Google Scholar identified studies evaluating prenatal exposures, epigenetic markers, and clinical outcomes. Study quality was assessed using the Joanna Briggs Institute criteria. Thirty-four studies (2009-2024) were included. Prenatal exposure to air pollutants, heavy metals, endocrine disruptors, and tobacco smoke was associated with global and gene-specific DNA methylation changes, altered miRNA profiles, and histone modifications in placental and cord-blood tissues. These epigenetic alterations were frequently linked to preterm birth, low birth weight, stillbirth, gestational diabetes, and hypertensive disorders of pregnancy. Environmental exposures during pregnancy are consistently associated with measurable epigenetic changes that parallel adverse birth outcomes, supporting their potential role as mechanistic mediators and biomarkers of risk.