Associations between prenatal exposure to phthalates and birth weight: A meta-analysis study

Previous studies have suggested that phthalates are associated with birth weight. However, most phthalate metabolites have not been fully explored. Therefore, we conducted this meta-analysis to assess the relationship between phthalate exposure and birth weight. We identified original studies that measured phthalate exposure and reported its association with infant birth weight in relevant databases. Regression coefficients (β) with 95% confidence intervals (CIs) were extracted and analyzed for risk estimation. Fixed-effects (I2 ≤ 50%) or random-effects (I2 > 50%) models were adopted according to their heterogeneity. Overall summary estimates indicated negative associations of prenatal exposure to mono-n-butyl phthalate (pooled β = −11.34 g; 95% CI: −20.98 to −1.70 g) and mono-methyl phthalate (pooled β = −8.78 g; 95% CI: −16.30 to −1.27 g). No statistical association was found between the other less commonly used phthalate metabolites and birth weight. Subgroup analyses indicated that exposure to mono-n-butyl phthalate was associated with birth weight in females (β = −10.74 g; 95% CI: −18.70 to −2.79 g). Our findings indicate that phthalate exposure might be a risk factor for low birth weight and that this relationship may be sex specific. More research is needed to promote preventive policies regarding the potential health hazards of phthalates