The association between mercury exposure during pregnancy and adverse birth outcomes: A systematic review and meta-analysis.

Studies have shown that mercury (Hg) exposure during pregnancy is associated with adverse birth outcomes (ABO) in infants, but the association between the two has not been systematically summarized. Therefore, we conducted a systematic review and meta-analysis of existing observational studies on the association between maternal Hg exposure (MHE) during pregnancy and ABO in infants to evaluate the association between them. We comprehensively searched all relevant literature published in three electronic databases (Web of Science, PubMed, Embase) from 2004 to June 2024. According to the heterogeneity, fixed effect model (I ≤ 50 %) or random effect model (I > 50 %) was used to pool the associated effect values. The results showed a positive association between MHE and low birth weight (LBW) (OR = 1.079, 95 % CI: 1.032-1.128) and no statistically significant association between and preterm birth (PTB) (OR = 1.044, 95 % CI: 0.956-1.140) and small-for-gestational-age (SGA) (OR = 1.006, 95 % CI: 0.983-1.030). In addition, each 10-fold increase in MHE during pregnancy was associated with abnormal Birth Anthropometrics. These findings suggest that MHE is a risk factor for LBW and is associated with abnormal anthropometric measurements at birth. However, there is insufficient evidence for Hg exposure and SGA, PTB. Further population-based studies are warranted to investigate these associations.