Prenatal Exposure to Phthalates and Anogenital Distance in Male Infants from a Low-Exposed Danish Cohort (2010-2012)

BACKGROUND: Phthalates comprise a large class of chemicals used in a variety of consumer products. Several have anti-androgenic properties, and in rodents prenatal exposure has been associated with reduced anogenital distance (AGD)-the distance from the anus to the genitals in male offspring. Few human studies have been conducted, but associations between the anti-androgenic phthalates and male AGD have been reported. OBJECTIVE: We aimed to study the association between phthalate exposure in late pregnancy in Danish women pregnant in 2010-2012 and AGD in their male infants at 3 months of age (n = 273). METHODS: In the Odense child cohort study, urinary concentrations of 12 phthalate metabolites of diethyl, di-n-butyl, diisobutyl, di(2-ethylhexyl), butylbenzyl, and diisononyl phthalate (DEP, DnBP, DiBP, DEHP, BBzP, and DiNP, respectively) were measured among 245 mothers of boys at approximately gestational week 28 (range, 20.4-30.4) and adjusted for osmolality. AGD, penile width, and weight were measured 3 months after the expected date of birth. Associations between prenatal phthalate and AGD and penile width were estimated using multivariable linear regression adjusting for age and weight-for-age standard deviation score. RESULTS: Phthalate levels were lower in this population than in a recent Swedish study in which phthalates were measured in the first trimester. No consistent associations were seen between any prenatal phthalate and AGD or penile width. Most associations were negative for exposures above the first quartile, and for ln-transformed exposures modeled as continuous variables, but there were no consistent dose-response patterns, and associations were not statistically significant (p > 0.05). CONCLUSION: We found no significant trends towards shorter AGD in boys with higher phthalates exposures in this low exposed Danish population.