This research was supported by the Intramural Research Program of the NIH, National Institute of Environmental Health Sciences. None of the authors has any conflict of interest to declare.

There are many studies based on self-reported menstrual cycle length, yet little is known about the validity of this measure. The authors used data collected in 1990 from 352 women born in Chicago, Illinois, aged 37-39 years. Women reported their usual cycle length and behavioral and reproductive characteristics at study enrollment and then completed daily menstrual diaries for up to 6 months. The authors compared this observed cycle length (geometric mean) with the reported length by using kappa coefficients. To assess systematic effects, they performed linear regression of the difference between reported and observed cycle length. Agreement between observed and reported cycle length was moderate. The crude overall kappa coefficient was 0.33; the kappa adjusted for within-woman sampling variability was 0.45 (95% confidence interval: 0.36, 0.55). On average, women overestimated their cycle length by 0.7 days (95% confidence interval: 0.3, 1.0). Reporting by sexually active women and women with a history of infertility was more accurate. Parity, body mass index, prior medical evaluation for irregular cycles, and exercise were all associated with systematic reporting differences. Studies that rely on self-reported cycle length could be prone to artifactual findings because of systematic covariate effects on reporting.

Objective To provide female age-related estimates of fecundity and incidence of infertility by history of prior pregnancy among women 30 to 44 years of age. Design Prospective, time-to-pregnancy cohort study Setting Community-based cohort Patient(s) Women, between 30 and 44 years of age, attempting to conceive for three or fewer months, and no known history of infertility, polycystic ovarian syndrome, or endometriosis Intervention None Main Outcome Measure (s) Fecundability and incidence of infertility Result Compared to women ages 30–31, fecundability was reduced by 14% in women 34–35 years of age (Fecundability Ratio (FR) 0.86, 95% CI: 0.68–1.08), 19% in women 36–37 years of age (FR 0.81,95% CI: 0.60–1.08, 30% in women 38–39 (FR 0.70, 95% CI: 0.48–1.01), 53% in women 40–41 (FR 0.47, 95% CI 0.28–0.78) and 59% in women 42–44 (FR 0.39, 95% CI 0.16–0.93). Fecundability did not differ between women ages 30–31 and women ages 32–33 years. In general, fecundability and cumulative probability of pregnancy was lower for women, who had never had a prior pregnancy. Conclusions Women experience a significant reduction in fecundity and increase in the probability of infertility in their late thirties. At any age over 30, women who have never conceived before have a lower probability of achieving a pregnancy.

BackgroundCertain phthalates and bisphenol A (BPA) show reproductive effects in animal studies and potentially affect human ovulation, conception, and pregnancy loss.ObjectivesWe investigated these chemicals in relation to follicular- and luteal-phase lengths, time to pregnancy, and early pregnancy loss (within 6 weeks of the last menstrual period) among women attempting pregnancy.MethodsWomen discontinuing contraception provided daily first-morning urine specimens and recorded days with vaginal bleeding for up to 6 months. Specimens had previously been analyzed for estrogen and progesterone metabolites and human chorionic gonadotropin. A total of 221 participants contributed 706 menstrual cycles. We measured 11 phthalate metabolites and BPA in pooled urine from three specimens spaced throughout each menstrual cycle. We analyzed associations between chemical concentrations and outcomes using linear mixed models for follicular- and luteal-phase lengths, discrete-time fecundability models for time to pregnancy, and logistic regression for early pregnancy loss.ResultsHigher concentrations of monocarboxyoctyl phthalate (MCOP) were associated with shorter luteal phase [2nd tertile vs. 1st tertile: –0.5 days (95% CI: –0.9, –0.1), 3rd vs. 1st: –0.4 days (95% CI: –0.8, 0.01), p = 0.04]. BPA was also associated with shorter luteal phase [2nd vs. 1st: –0.8 days (95% CI: –1.2, –0.4), 3rd vs. 1st: –0.4 days (95% CI: –0.8, 0.02), p = 0.001].ConclusionsBPA and MCOP (or its precursors) were associated with shorter luteal phase. Menstrual cycle–specific estimates of urinary BPA and phthalate metabolites were not associated with detrimental alterations in follicular-phase length, time to pregnancy, or early pregnancy loss, and in fact, DEHP [di(2-ethylhexyl) phthalate] metabolites {MEOHP [mono(2-ethyl-5-oxohexyl) phthalate] and ΣDEHP} were associated with reduced early loss. These findings should be confirmed in future human studies.CitationJukic AM, Calafat AM, McConnaughey DR, Longnecker MP, Hoppin JA, Weinberg CR, Wilcox AJ, Baird DD. 2016. Urinary concentrations of phthalate metabolites and bisphenol A and associations with follicular-phase length, luteal-phase length, fecundability, and early pregnancy loss. Environ Health Perspect 124:321–328; http://dx.doi.org/10.1289/ehp.1408164