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

Abstract

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 <400μg/day of food folate, but not among women consuming ≥400μg/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.

Keywords: Bisphenol A; Folate; In vitro fertilization; Methyl donors.

Copyright © 2016 Elsevier Inc. All rights reserved.

Figures

Figure 1. Effect modification of folate intake from food sources on the relation between implantation (p-interaction=0.04), clinical pregnancy (p-interaction=0.07) and live birth (p-interaction=0.16), with urinary BPA concentrations (μg/L) (n=248 fresh cycles)

The adjusted proportion of initiated cycles (95% CI) resulting in implantation, clinical pregnancy, and live birth across quartiles of specific gravity adjusted urinary BPA concentrations by folate intake are presented. Models are adjusted for age (continuous), BMI (continuous), race (white vs. nonwhite), day 3 FSH result (continuous), E2 trigger result (continuous), protocol type (luteal phase agonist, antagonist, and flare), infertility diagnosis (male, female and unexplained), intake of vitamin b12 (continuous), intake of folate from supplements (continuous), calorie intake (continuous), intake of soy foods (continuous) and adherence to data-derived dietary patterns (continuous). Implantation was defined as a serum β-hCG level > 6 mIU/mL typically measured 17 days (range 15–20 days) after egg retrieval, clinical pregnancy as the presence of an intrauterine pregnancy confirmed by ultrasound and live birth as the birth of a neonate on or after 24 weeks gestation. *Indicates a p-value+Indicates a p-value<0.05 comparing the fourth quartile vs. the three bottom quartiles. Notes: Q1-3 was a unique group including Q1, Q2 and Q3.

Figure 1. Effect modification of folate intake from food sources on the relation between implantation (p-interaction=0.04), clinical pregnancy (p-interaction=0.07) and live birth (p-interaction=0.16), with urinary BPA concentrations (μg/L) (n=248 fresh cycles)

The adjusted proportion of initiated cycles (95% CI) resulting in implantation, clinical pregnancy, and live birth across quartiles of specific gravity adjusted urinary BPA concentrations by folate intake are presented. Models are adjusted for age (continuous), BMI (continuous), race (white vs. nonwhite), day 3 FSH result (continuous), E2 trigger result (continuous), protocol type (luteal phase agonist, antagonist, and flare), infertility diagnosis (male, female and unexplained), intake of vitamin b12 (continuous), intake of folate from supplements (continuous), calorie intake (continuous), intake of soy foods (continuous) and adherence to data-derived dietary patterns (continuous). Implantation was defined as a serum β-hCG level > 6 mIU/mL typically measured 17 days (range 15–20 days) after egg retrieval, clinical pregnancy as the presence of an intrauterine pregnancy confirmed by ultrasound and live birth as the birth of a neonate on or after 24 weeks gestation. *Indicates a p-value+Indicates a p-value<0.05 comparing the fourth quartile vs. the three bottom quartiles. Notes: Q1-3 was a unique group including Q1, Q2 and Q3.