Figure 1.

Effect of the modification by soy intake of the relation between implantation (P for interaction = .02), clinical pregnancy (P for interaction = .03), and live birth (P for interaction = .01) and urinary BPA concentrations (micrograms per liter) (n = 347 fresh cycles). Implantation (95% confidence interval) per initiated cycle across quartiles of urinary BPA concentrations (represented by the medians for each quartile) by soy intake is presented. Models are adjusted for age (continuous), BMI (continuous), race (white, black, Asian, and others), and infertility diagnosis (male, female, and unexplained). Tests for trend were performed using the median level of urinary BPA level in each quartile as a continuous variable in the model. Implantation was defined as a serum β-hCG level of >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 of gestation. *, P < .05 comparing that quartile vs first quartile.