Association of prenatal exposure to phenols and parabens with birth size: A systematic review and meta-analysis

Phenols and parabens are endocrine-disrupting chemicals and are widely used in daily life products due to their antibacterial action. Previous studies suggest associations of prenatal exposure to phenols and parabens with fetal development; however, such findings are rare and inconsistent. The aim of this review and meta-analysis is to estimate the associations between maternal exposure to phenols and parabens and birth size. We identified 21 relevant studies that met the inclusion criteria through databases of PubMed, Cochrane, EMBASE and Qvid Medline. The last search was in July 3, 2019. The heterogeneity and possibility of publication bias among included studies were assessed by Q-statistic and Begg’s test, respectively. Meta-analysis revealed that prenatal exposure to triclosan [number of studies (n) = 12, regression coefficient (β) = −0.04 g; 95% confidence interval (CI): −0.139, 0.059], benzophenone-3 (n = 10, β = −0.001 g; 95% CI: −0.013, 0.012), bisphenol A (n = 9, β = −0.049 g; 95% CI: −0.199, 0.101), 2–4-dichlorophenols (n = 6, β = −14.124 g; 95% CI: −29.971, 1.723), 2–5-dichlorophenols (n = 6, β = −0.061 g; 95% CI: −0.196, 0.074) and parabens were negatively associated with fetal birth weight. Most of them were insignificant. Inconsistent and insignificant associations were detected between exposure to phenols and parabens and other birth outcomes. Subgroup analysis suggested that heterogeneity in our meta-analysis was mainly attributed to the studies conducted in developed countries and samples collected in the second trimester. Insignificant and controversial associations of maternal exposure to phenols and parabens with birth size were observed in our study. The study design and methods of the included studies are inconsistent, and the effects of environmental pollutants on human health are complex. Further cohort studies with large samples and a consistent approach are thus required to evaluate the associations of maternal exposure to phenols and parabens with birth size.