Serum caffeine and paraxanthine concentrations and menstrual cycle function: correlations with beverage intakes and associations with race, reproductive hormones, and anovulation in the BioCycle Study.

BACKGROUND: Clinicians often recommend limiting caffeine intake while attempting to conceive; however, few studies have evaluated the associations between caffeine exposure and menstrual cycle function, and we are aware of no previous studies assessing biological dose via well-timed serum measurements. OBJECTIVES: We assessed the relation between caffeine and its metabolites and reproductive hormones in a healthy premenopausal cohort and evaluated potential effect modification by race. DESIGN: Participants (n = 259) were followed for ≤2 menstrual cycles and provided fasting blood specimens ≤8 times/cycle. Linear mixed models were used to estimate associations between serum caffeine biomarkers and geometric mean reproductive hormones, whereas Poisson regression was used to assess risk of sporadic anovulation. RESULTS: The highest compared with the lowest serum caffeine tertile was associated with lower total testosterone [27.9 ng/dL (95% CI: 26.7, 29.0 ng/dL) compared with 29.1 ng/dL (95% CI: 27.9, 30.3 ng/dL), respectively] and free testosterone [0.178 ng/mL (95% CI: 0.171, 0.185 ng/dL) compared with 0.186 ng/mL (95% CI: 0.179, 0.194 ng/dL), respectively] after adjustment for age, race, percentage of body fat, daily vigorous exercise, perceived stress, depression, dietary factors, and alcohol intake. The highest tertiles compared with the lowest tertiles of caffeine and paraxanthine were also associated with reduced risk of anovulation [adjusted RRs (aRRs): 0.39 (95% CI: 0.18, 0.87) and 0.40 (95% CI: 0.18, 0.87), respectively]. Additional adjustment for self-reported coffee intake did not alter the reproductive hormone findings and only slightly attenuated the results for serum caffeine and paraxanthine and anovulation. Although reductions in the concentrations of total testosterone and free testosterone and decreased risk of anovulation were greatest in Asian women, there was no indication of effect modification by race. CONCLUSION: Caffeine intake, irrespective of the beverage source, may be associated with reduced testosterone and improved menstrual cycle function in healthy premenopausal women.

Understanding culturally motivated requests from Orthodox Jewish women to delay ovulation.

We report here on the cultural reasons motivating some idiosyncratic requests from married Orthodox Jewish women to delay ovulation. Understanding and respecting the patient's individual concerns and religious values, including the complex psychological, sociological and cultural factors that they involve, is part of good medical practice.

Attitudes toward menstrual suppression and conformity to feminine norms in young and middle-aged Mexican women.

Seventy seven college students and 66 middle-aged Mexican women completed an adapted questionnaire of attitudes toward menstrual suppression and the Conformity to Feminine Norms Inventory. Participants showed a great interest in menstrual suppression, but few were familiar with this issue. Young women would like to have longer menstrual cycles than monthly and were more supportive of menstrual suppression than middle-aged women. Women who would prefer to have longer menstrual cycles showed less conformity to feminine norms. These findings are discussed in light of differences between age cohorts, and the relationship between the studied variables and attitudes toward menstruation.