Effects of butyl benzyl phthalate exposure during pregnancy and lactation on the post-involution mammary gland

Prenatal phthalate exposure and anogenital distance in infants at 12 months

OBJECTIVE

Anogenital distance (AGD) is a postnatal marker of in utero exposure to androgens and anti-androgens, and a predictor of reproductive health. We examined the association between gestational exposure to phthalates and AGD in male and female infants.

METHODS

In 506 mother-infant pairs (276 males, 230 females), we measured urinary concentrations of phthalate metabolites at < 18 and 18-25 weeks of gestation and AGD at child age 12.9 months (95 % range 11.4-21.1). Phthalate metabolite concentrations were adjusted for urinary dilution, averaged, and natural log-transformed. We measured anus-clitoris distance (AGDac) and anus-fourchette distance (AGDaf) in females, and anus-scrotum distance, anus-penis distance, and penile width in males. We used linear regression and partial-linear single-index (PLSI) models to examine associations between phthalates and AGD as single pollutants and in mixture.

RESULTS

Fifty-eight percent of mothers were Hispanic, followed by 27 % non-Hispanic White. Higher exposures to ∑di-isononyl(phthalate) (∑DiNP) was associated with longer AGDaf [1.28 mm (95 % confidence interval [CI]: 0.52, 2.03) and 0.97 mm (95 %CI: 0.25, 1.69), respectively]. Higher exposures to ∑di(2-ethylhexyl)phthalate (∑DEHP) was associated with longer AGDac [2.80 mm (95 %CI: 1.17, 4.44), and 1.90 mm (95 %CI: 0.76, 3.04), respectively]. No association was observed between phthalate metabolites and AGD in males after multiple testing correction. In mixture analyses, ∑DiNP and ∑DEHP were the main contributors to longer AGD in females. We also detected an interaction between ∑DiNP and ∑DEHP in association with AGD in females.

CONCLUSION

Early pregnancy phthalate exposure was associated with longer AGD in female infants. Biological mechanisms underlying these associations should be further investigated.

Effects of a TAML catalyst on mice exposed during pregnancy and lactation

Tetra-amido macrocyclic ligands (TAMLs) are catalysts designed to mimic endogenous peroxidases that can degrade pollutants. Before TAMLs gain widespread use, it is first important to determine if they have endocrine disrupting properties. In this study, we evaluated the effects of the iron TAML, NT7, on hormone-sensitive outcomes in mice exposed during pregnancy and lactation, and on their litters prior to weaning. We administered NT7 at one of three doses to mice via drinking water prior to and then throughout pregnancy and lactation. Two hormonally active pharmaceuticals, ethinyl estradiol (EE2) and flutamide (FLUT), a known estrogen receptor agonist and androgen receptor antagonist, respectively, were also included. In the females, we measured pre- and post-parturition weight, length of pregnancy, organ weights at necropsy, and morphology of the mammary gland at the end of the lactational period. We also quantified maternal behaviors at three stages of lactation. For the offspring, we measured litter size, litter weights, and the achievement of other developmental milestones. We observed only one statistically significant effect of NT7, a decrease in the percentage of pups with ear opening at postnatal day 5. This contrasts with the numerous effects of EE2 on both the mother and the litter, as well as several modest effects of FLUT. The approach taken in this study could provide guidance for future studies that aim to evaluate novel compounds for endocrine disrupting properties.