Urinary bisphenol A, phthalates, and couple fecundity: the Longitudinal Investigation of Fertility and the Environment (LIFE) Study.

OBJECTIVE: To assess the relationship between environmental chemicals and couple fecundity or time to pregnancy (TTP).

DESIGN: Prospective cohort.

SETTING: Communities of targeted populations with reported exposure.

PATIENT(S): 501 couples recruited upon discontinuing contraception to become pregnant, 2005-2009.

INTERVENTION(S): None.

MAIN OUTCOME MEASURE(S): Fecundability odds ratios (FORs) and 95% confidence intervals (CIs) estimated for each partner's chemical concentrations adjusted for age, body mass index, cotinine, creatinine, and research site while accounting for time off contraception.

RESULT(S): Couples completed interviews and anthropometric assessments and provided the urine specimens for quantification of bisphenol A (BPA) and 14 phthalate metabolites, which were measured using high-performance liquid chromatography with electrospray triple-quadrupole mass spectrometer. Women recorded menstruation and pregnancy test results in daily journals. Couples were evaluated until a positive human-chorionic gonadotropin pregnancy test or 12 cycles without pregnancy. Neither female nor male BPA concentration was associated with TTP (FOR 0.98; 95% CI, 0.86, 1.13 and FOR 1.04; 95% CI, 0.91, 1.18, respectively). Men's urinary concentrations of monomethyl, mono-n-butyl, and monobenzyl phthalates were associated with a longer TTP (FOR 0.80; 95% CI, 0.70, 0.93; FOR 0.82, 95% CI, 0.70, 0.97; and FOR 0.77, 95% CI, 0.65 0.92, respectively).

CONCLUSION(S): Select male but not female phthalate exposures were associated with an approximately 20% reduction in fecundity, underscoring the importance of assessing both partners' exposure to minimize erroneous conclusions.