Female dietary antioxidant intake and time to pregnancy among couples treated for unexplained infertility

Objective To determine whether increased antioxidant intake in women is associated with shorter time to pregnancy (TTP) among a cohort of couples being treated for unexplained infertility. Design Secondary data analysis of a randomized controlled trial. Setting Academic medical center associated with a private infertility center. Patients Females with unexplained infertility. Interventions None. Main Outcome Measure(s) The time it took to establish a pregnancy that led to a live birth. Result(s) Mean nutrient intake exceeded the estimated average requirement (EAR) for vitamins C and E. No differences in mean intake of any of the antioxidants were noted between women who delivered a live-born infant during the study period vs. those who did not. In multivariable models, intake of β-carotene from dietary supplements was associated with shorter TTP among women with body mass index (BMI) ≥25 kg/m² (hazard ratio [HR] 1.29, 95% confidence interval [CI] 1.09-1.53) and women <35 y (HR 1.19, 95% CI 1.01-1.41). Intake of vitamin C from dietary supplements was associated with shorter TTP among women with BMI <25 kg/m² (HR 1.09, 95% CI 1.03-1.15) and women <35 y (HR 1.10, 95% CI 1.02-1.18). Intake of vitamin E from dietary supplements among women ≥35 y also was associated with shorter TTP (HR 1.07, 95% CI 1.01-1.13). Conclusion(s) Shorter TTP was observed among women with BMI <25 kg/m² with increasing vitamin C, women with BMI ≥25 kg/m² with increasing β-carotene, women <35 y with increasing β-carotene and vitamin C, and women ≥35 y with increasing vitamin E. Clinical Trial Registration Number NCT00260091.