Impact of female age and nulligravidity on fecundity in an older reproductive age cohort

Objective: To provide female age-related estimates of fecundity and incidence of infertility by history of prior pregnancy among women 30-44 years of age. Design: Prospective, time-to-pregnancy cohort study. Setting: Not applicable. Patient(s): Women, between 30 and 44 years of age, attempting to conceive for < 3 months, and no known history of infertility, poly cystic ovarian syndrome (PCOS), or endometriosis. Intervention(s): Not applicable. Main Outcome Measure(s): Fecundability and incidence of infertility. Result(s): Compared to women aged 30-31 years, fecundability was reduced by 14% in women 34-35 years of age (fecundability ratio [FR] 0.86, 950/o confidence interval [CI] 0.68-1.08), 190/o in women 36-37 years of age (FR 0.81, 950/o CI 0.60-1.08, 300/o in women 3839 years of age (FR 0.70, 950/o CI 0.48-1.01), 530/o in women 40-41 years of age (FR 0.47, 95% CI 0.28-0.78), and 59% in women 4244 years of age (FR 0.39, 95o/ci CI 0.16-0.93). Fecundability did not differ between women aged 30-31 years and 32-33 years. In general, fecundability and cumulative probability of pregnancy was lower for women who had never had a prior pregnancy. Conclusion(s): Women experience a significant reduction in fecundity and increase in the probability of infertility in their late thirties. At any age >30 years, women who have never conceived have a lower probability of achieving a pregnancy. Clinical Trial Registration Number: NCT01028365. (Fertil Steril'A' 2016;105:1584-8. (C) 2016 by American Society for Reproductive Medicine.)