Fecundability in relation to use of fertility awareness indicators in a North American preconception cohort study.

OBJECTIVE: To quantify the frequency of use of selected fertility awareness indicators and to assess their influence on fecundability. DESIGN: Web-based prospective cohort study. SETTING: Not applicable. PATIENT(S): Female pregnancy planners, aged 21-45 years, attempting conception for ≤6 cycles at study entry. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): We ascertained time to pregnancy, in menstrual cycles, with bimonthly questionnaires. We estimated adjusted fecundability ratios (FRs) and confidence intervals (CIs) using proportional probabilities models, controlling for age, income, education, smoking, intercourse frequency, and other lifestyle and reproductive factors. RESULT(S): A total of 5,688 women were analyzed, with a mean age of 29.9 years and mean time trying of 2.1 cycles at baseline; 30% had ever been pregnant. At baseline, 75% were using one or more fertility indicators (counting days or charting menstrual cycles [71%], measuring basal body temperature [BBT, 21%], monitoring cervical fluid [39%], using urine LH tests [32%], or feeling for changes in position of the cervix [12%]). Women using any fertility indicator at baseline had higher subsequent fecundability (adjusted FR 1.25, 95% CI 1.16-1.35) than those not using any fertility indicators. For each individual indicator, adjusted FRs ranged from 1.28-1.36, where 1.00 would indicate no relation with fecundability. The adjusted FR for women using a combination of charting days, cervical fluid, and urine LH was 1.48 (95% CI 1.31-1.67) relative to women using no fertility indicators. CONCLUSION(S): In a North American preconception cohort study, use of fertility indicators indicating the fertile window was common, and was associated with greater fecundability.

Sleep and female reproduction.

PURPOSE OF REVIEW: Sleep disturbances are increasing in prevalence in North America. There is growing evidence that poor sleep quality and short sleep duration may adversely affect circadian rhythms, which in turn may affect female reproduction. The objective of this review is to evaluate recent literature on the association between sleep disturbances and female reproduction. RECENT FINDINGS: There is accumulating evidence that sleep quality and duration are important for female reproduction, but epidemiologic research is limited. Recent studies provide suggestive evidence that sleep disorders are associated with increased menstrual irregularity, subfertility/infertility, and poor pregnancy and birth outcomes. Mechanisms underlying these associations are likely to be multifactorial and complex. In addition to genetics, circadian disruption may impact reproductive outcomes through dysregulation of the hypothalamic-pituitary-adrenal axis, insulin resistance, oxidative stress, and systemic inflammation. Recommendations for future studies include: use of prospective study designs; assessment of populations not already experiencing reproductive disorders; more detailed and accurate assessments of sleep such as validated self-reported measures or objective sleep measures (e.g. actigraphy); comprehensive assessment of potential confounders and mediators; and elucidation of biologic mechanisms. SUMMARY: There is a growing body of literature showing evidence that sleep disturbances influence female reproduction, although further epidemiologic research is needed.

Female sleep patterns, shift work, and fecundability in a North American preconception cohort study.

OBJECTIVE: To prospectively evaluate the association between female sleep patterns, shift work, and fecundability. DESIGN: Web-based preconception cohort study, Pregnancy Study Online (PRESTO). SETTING: Not applicable. PATIENT(S): North American Women aged 21-45 years attempting pregnancy. INTERVENTION(S): Not applicable. MAIN OUTCOME MEASURE(S): At baseline, self-reported average sleep duration per 24-hour period in the previous month, the frequency of trouble sleeping within the last 2 weeks (as measured by the Major Depression Inventory), and shift work patterns. Pregnancy status determined by follow-up questionnaires completed every 8 weeks for up to 12 months or until conception. RESULT(S): The analyses were restricted to 6,873 women attempting pregnancy for ≤6 months at enrollment from June 2013 through September 2018. We used proportional probabilities regression models to estimate fecundability ratios (FRs) and 95% confidence intervals (CIs), adjusting for potential confounders. Relative to 8 hours of sleep per day, FRs for <6, 6, 7, and ≥9 hours of sleep/day were 0.89 (95% CI, 0.75-1.06), 0.95 (95% CI, 0.86-1.04), 0.99 (95% CI, 0.92-1.06), and 0.96 (95% CI, 0.84-1.10), respectively. Compared with no trouble sleeping, FRs for trouble sleeping <50% of the time or trouble sleeping >50% of the time were 0.93 (95% CI, 0.88-1.00) and 0.87 (95% CI, 0.79-0.95), respectively. The results were slightly stronger among women with higher depressive symptoms and perceived stress levels. There was no association between shift work and fecundability. CONCLUSION(S): Trouble sleeping at night was associated with modestly reduced fecundability. A weaker inverse association was observed between shorter sleep duration and fecundability.