Iron intake and risk of ovulatory infertility.

Abstract

To evaluate whether iron supplement use or greater intake of total, heme and nonheme iron is associated with lower risk of ovulatory infertility. We conducted a prospective cohort study among 18,555 married, premenopausal women without a history of infertility who attempted a pregnancy or became pregnant between 1991 and 1999 (mean baseline age+/-standard deviation 32.6+/-3.6). Diet was assessed twice during follow-up and prospectively related to the incidence of infertility due to ovulatory disorder. During the 8 years of follow-up, 438 women reported infertility due to ovulatory disorder. Women who consumed iron supplements had a significantly lower risk of ovulatory infertility than women who did not use iron supplements (relative risk 0.60, 95% confidence interval 0.39-0.92), after adjusting for potential confounders. Total nonheme iron intake, primarily consumed as multivitamins and iron supplements, was inversely associated with the risk of infertility (relative risk Quintile 1 compared with 5, 95% confidence interval 0.39-0.92; P, trend .005.) Heme iron intake was unrelated to ovulatory infertility in multivariable adjusted analyses. Consumption of iron supplements and nonheme iron from other sources may decrease the risk of ovulatory infertility. II-2.