Dietary fat intake and reproductive hormone concentrations and ovulation in regularly menstruating women

Appetite and Energy Intake in Laboratory and Free-Living Conditions Remain Consistent Across Menstrual Cycle Phases when Using Precise Measurement Methods

Smith M et al., 2025

Self-reported dietary intake varies across menstrual cycle phases, but objective assessments of dietary intake together with appetite and resting metabolic rate (RMR) are limited. This study aimed to assess differences in appetite, dietary intake, and RMR during two hormonally-distinct menstrual cycle phases in laboratory and free-living settings. Healthy premenopausal females with predictable normal-length menstrual cycles one in the late-follicular and one in the mid-luteal phase. Menstrual cycle phases were identified using urinary luteinizing hormone surge and cycle days. Participants consumed a 2-day energy- and macronutrient-balanced run-in diet prior to each visit. RMR was measured with indirect calorimetry, followed by appetite ratings before and after a standardized breakfast, and completed a food cravings questionnaire. Appetite was also tracked for 2.5 days post-visit in a free-living environment. Ad libitum energy and macronutrient intake were measured using pre-weighed plus weighing of uneaten food at an in-laboratory lunch meal, as well as during the 2.5-day free-living period. Eighteen participants were included (age: 21±4 years; 21.2±1.5 kg/m 2 ). There were no differences between in-laboratory ad libitum energy or macronutrient intakes, appetite, or food cravings between phases. RMR did not differ between phases, although the mid-luteal phase RMR trended toward higher (104±218 kcal/day higher ; P =0.074). No main nor interaction effects for phase and time were observed for free-living dietary intake nor appetite ratings. Accurate measurements show no differences in appetite or energy intake between menstrual cycle phases, though RMR may be slightly elevated in the luteal phase.

Hormonal Regulation of the Menstrual Cycle: The Evolution of Concepts

Gruhn JG et al., 1989

Modeling Fertile Window Differences Across the Reproductive Lifespan with Quantitative Urine Hormone Monitoring of the Menstrual Cycle

Bouchard TP et al., 2025

Background Reproductive hormones of the fertile window are often referenced to women in regular cycles, but this may not be representative of the hormonal profiles of women in different circumstances like polycystic ovarian syndrome, the postpartum period, and the perimenopause transition. This observational cohort study sought to identify the variability in the hormones of the fertile window in various reproductive categories and to establish potential thresholds for each category based on hormone measurements with the Mira urinary hormone monitor. Results A total of 57 women (ages 22–51) in various circumstances (regular cycles, polycystic ovarian syndrome, postpartum and perimenopause) tracked Mira urine hormone measurements (estrone-3-glucuronide, luteinizing hormone, pregnanediol glucuronide), contributing 444 cycles of data. Using additive mixed models, hormone values were stratified by the four different reproductive categories. The perimenopause and polycystic ovararian syndrome groups demonstrated relative hypoestrogenic states, while the perimenopause group showed low luteal pregnanediol glucuronide and the polycystic ovarian syndrome group showed high luteal pregnanediol glucuronide. The perimenopause group had higher luteinizing hormone values throughout the whole cycle. Conclusion The fertile window hormone thresholds vary depending on a woman’s specific reproductive category. Women in different circumstances should not necessarily use the same hormonal thresholds for the fertile window and ovulation. A larger dataset with ultrasound correlation to ovulation is required to delineate the fertile window with more precision. Hormone differences across the menstrual cycle could be used for targeted treatments in polycystic ovarian syndrome and perimenopause women.

Changes in macronutrient, micronutrient, and food group intakes throughout the menstrual cycle in healthy, premenopausal women

Gorczyca AM et al., 2016·European Journal of Nutrition