Our objective was to determine if maternal first trimester urinary phthalate concentrations are associated with reduced penile length (PL) or width (PW) at birth in full term singletons.

First trimester phthalate metabolite urinary concentrations were obtained from mothers participating in a Canadian pregnancy cohort study (MIREC). PL and PW were measured shortly after birth in the male offspring. Univariate and multivariable linear regressions were performed to study associations between maternal phthalate exposure and penile measurements, adjusting for confounders.

On univariate analysis of 170 mother-infant pairs, PW showed an inverse relationship with the concentration of mono-3-carboxypropyl phthalate (MCPP-p = 0.016), which was not confirmed on multivariable analysis. On multivariable analysis controlling for infant’s size and other confounders, no statistically signficant associations between phthalate metabolite concentrations and PL or PW were identified.

In this population of Canadian women, there was no strong evidence to suggest an association between maternal first trimester urinary phthalates with PL or PW in term singletons.