Dietary folate intake and modification of the association of urinary bisphenol A concentrations with in vitro fertilization outcomes among women from a fertility clinic

- High urinary BPA concentrations were associated with lower probability of implantation, clinical pregnancy and live birth, among women who consumed <400 μg/day of food folate.
- Urinary BPA concentrations were not associated with probability of implantation, clinical pregnancy and live birth, among women who consumed ≥400 μg/day of food folate.
- We found no evidence of interactions with total or supplemental folate intake, nor with intake of vitamin B12, choline or betaine.

Experimental data in rodents suggest that the effects of bisphenol A (BPA) on oocyte development may be modified by dietary methyl donors. Whether the same interaction exists in humans is unknown. We evaluated whether intake of methyl donors modified the associations between urinary BPA concentrations and treatment outcomes among 178 women who underwent 248 IVF cycles at a fertility center in Boston between 2007 and 2012. Participants completed a validated food frequency questionnaire and provided up to two urine samples per treatment cycle. High urinary BPA concentrations were associated with a 66% lower probability of implantation (p = 0.007) among women who consumed <400 μg/day of food folate, but not among women consuming ≥400 μg/day (21% higher probability of implantation, p = 0.18) (p,interaction = 0.04). A similar pattern was observed for probability of clinical pregnancy (p,interaction = 0.07) and live birth (p,interaction = 0.16). These results are consistent with previous animal data but further evaluation in other human populations is needed.