The Association between Maternal Endocrine-Disrupting Chemical Exposure during Pregnancy and the Incidence of Male Urogenital Defects: A Systematic Review and Meta-Analysis

Abstract

The increasing incidence of hypospadias and cryptorchidism, coupled with the widespread presence of endocrine-disrupting chemicals (EDCs), has raised concerns about the potential impact of these environmental factors on male urogenital development. This systematic review and meta-analysis aims to evaluate the association between maternal exposure to various EDCs and the risk of hypospadias and cryptorchidism. We conducted a comprehensive search of PubMed, Scopus, Web of Science, and Cochrane databases from inception until May 2024. We included case-control and cohort studies that examined the association between maternal EDC exposure and hypospadias or cryptorchidism, reporting adjusted odds ratios (aOR) or crude odds ratios (cOR). Data were extracted and pooled using a random effects model, and heterogeneity was assessed using the Q test and I-square statistics. The risk of bias was evaluated using the Newcastle–Ottawa Scale (NOS). A total of 48 studies were included in the systematic review, with 46 studies included in the meta-analysis. The pooled analysis revealed a significant association between maternal EDC exposure and an increased risk of hypospadias (aOR = 1.26, 95% CI: 1.18–1.35, p < 0.0001) and cryptorchidism (aOR = 1.37, 95% CI: 1.19–1.57, p < 0.001). Subgroup analyses showed that exposure to pesticides, phthalates, alkyl phenolic compounds (ALKs), and heavy metals significantly increased the risk of hypospadias. In contrast, polychlorinated biphenyls (PCBs) did not show a significant association. Significant associations were found with pesticide and PCB exposure for cryptorchidism, but not with phthalate, ALK, or heavy metal exposure. Maternal exposure to certain EDCs is associated with an increased risk of hypospadias and cryptorchidism in male children. These findings underscore the importance of addressing environmental and occupational exposures during pregnancy to mitigate potential risks. Further research is needed to elucidate the mechanisms by which EDCs affect urogenital development and to develop effective interventions to reduce exposure among vulnerable populations.