Association between prenatal exposure to perfluoroalkyl substances and anogenital distance in female neonates

The Effect of Various Environmental Pollutants on the Reproductive Health in Children: A Brief Review of the Literature

PURPOSE OF REVIEW

Environmental pollutants in air, water, soil, and food are a significant concern due to their potential adverse effects on fetuses, newborns, babies, and children. These chemicals, which pass to fetuses and babies through trans-placental transfer, breast milk, infant formula, dermal transfer, and non-nutritive ingestion, can cause health problems during childhood. This review aims to discuss how exposure to various environmental pollutants in early life stages can disrupt reproductive health in children.

RECENT FINDINGS

Environmental pollutants can affect Leydig cell proliferation and differentiation, decreasing testosterone production throughout life. This may result in cryptorchidism, hypospadias, impaired semen parameters, and reduced fertility. Although many studies on female reproductive health cannot be interpreted to support causal relationships, exposure to pollutants during critical windows may subsequently induce female reproductive diseases, including early or delayed puberty, polycystic ovary syndrome, endometriosis, and cancers. There is growing evidence that fetal and early-life exposure to environmental pollutants could affect reproductive health in childhood. Although diet is thought to be the primary route by which humans are exposed to various pollutants, there are no adopted nutritional interventions to reduce the harmful effects of pollutants on children's health. Therefore, understanding the impact of environmental contaminants on various health outcomes may inform the design of future human nutritional studies.

Prenatal per- and polyfluoroalkyl substances exposure and gut microbiota of infants: A prospective cohort study

Prenatal exposure to per- and polyfluoroalkyl substances (PFASs) has been reported to be linked to a series of adverse health outcomes in mothers and their children. As the gut microbiota is a sensitive biomarker for assessing the toxicity of environmental contaminants, this study attempted to investigate whether prenatal PFASs exposure was associated with the gut microbiota of infants. Based on the Shanghai-Minhang Birth Cohort Study, this prospective cohort study included 69 mother-infant pairs. Fasting blood samples were collected from pregnant women for the PFASs assay. We collected fecal samples of infants at 1 year of age and analyzed the V3-V4 hypervariable region of the bacterial 16 S rRNA gene by high-throughput sequencing. Among the detected 11 PFASs, the concentration of perfluorooctanoic acid (22.19 ng/mL) was the highest, followed by perfluorooctane sulfonic acid (12.08 ng/mL). Compared with infants whose mothers' total PFASs concentrations during pregnancy were at the 40th percentile or lower (reference group), the species richness and diversity of microbiota were lower in infants prenatally exposed to a high level of PFASs (the sum of PFASs concentrations above the 60th percentile). Prenatal exposure to PFASs was associated with a higher proportion of Acidaminococcaceae, Acidaminococcus, Megamonas, Megasphaera micronuciformis and Megamonas funiformis in infants. The changes of the species have been suggested to be associated with immune and metabolic dysfunction in humans. Functional alterations of gut microbiota due to PFASs exposure were dominated by an enrichment of butanoate metabolism. Our preliminary findings may shed light on the potential role of the microbiota underlying the well-known impact of prenatal PFASs exposure on health outcomes of humans in later life.

Prenatal exposure to fine particulate matter and newborn anogenital distance: a prospective cohort study

BACKGROUND

Considerable attention has been paid to reproductive toxicity of fine particulate matter (PM_2.5). However, the relationship between prenatal PM_2.5 exposure and anogenital distance (AGD) has not been well studied. We aim to investigate the potential effects of prenatal exposure to PM_2.5 on newborn AGD.

METHODS

Prenatal PM_2.5 exposure of 2332 participates in Shanghai (2013-2016) was estimated using high-performance machine learning models. Anoscrotal distance (AGDas) in male infants and anofourchette distance (AGDaf) in female infants were measured by well-trained examiners within 3 days after birth. We applied multiple linear regression models and multiple informant models to estimate the association between prenatal PM_2.5 exposure and AGD.

RESULTS

Multiple linear regression models showed that a 10 μg/m³ increase in PM_2.5 exposure during full pregnancy, the second and third trimesters was inversely associated with AGDas (adjusted beta = - 1.76, 95% CI: - 2.21, - 1.31; - 0.73, 95% CI: - 1.06, - 0.40; and - 0.52; 95% CI: - 0.87, - 0.18, respectively) in males. A 10 μg/m³ increase in PM_2.5 exposure during the full pregnancy, the first, second, and third trimesters was inversely associated with AGDaf (adjusted beta = - 4.55; 95% CI: - 5.18, - 3.92; - 0.78; 95% CI: - 1.10, - 0.46; - 1.11; 95% CI: - 1.46, - 0.77; - 1.45; 95% CI: - 1.78, - 1.12, respectively) in females after adjusting for potential confounders. Multiple informant models showed consistent but slightly attenuated associations.

CONCLUSION

Our study observed a significant association between gestational PM_2.5 exposure during pregnancy and shortened AGD in newborns, and provided new evidence on potential reproductive toxicity of prenatal PM_2.5 exposure.