FemiClock: Non-invasive Tools Development (Salivary and Hair Progesterone) for Ovulation Detection in Heathy Women With Regular Menstrual Cycles Without Contraception.

Inclusion criteria

• Women aged 18 to 40 years, with a body mass index (BMI) between 19.0 and 29.9 kg/m². (Women with low or high BMI were excluded due to extensive literature showing a negative impact of extreme BMI values on the hypothalamic-pituitary-ovarian axis.)
• Women not using hormonal contraception (or using a non-hormonal copper intrauterine device), or who discontinued hormonal contraception more than 3 months prior to enrollment and do not plan to resume contraception during the 3 study menstrual cycles.
• Women with regular menstrual cycles between 25 and 35 days, with cycle length variability (difference between shortest and longest cycle) strictly less than 7 days.
• Women owning a smartphone (to enable collection and transmission of data recorded by a study-provided smartwatch).
• Exclusive daytime workers (no night or shift work).
• Hair length greater than 5 cm from root to tip, and willingness to provide a hair sample.
• Individuals affiliated with a national health insurance system or equivalent coverage.
• Individuals able to understand the study objectives and risks and willing to provide written informed consent (dated and signed).

Exclusion criteria

• Known fertility disorder.
• Night work and/or shift work within the 6 months prior to enrollment (between 9:00 p.m. and 6:00 a.m.).
• Untreated endocrine disorders or gynecological conditions that may affect menstrual cycles and/or ovulation, including clinical hyperandrogenism.
• History of cancer within the past 5 years.
• History of severe psychiatric disorder.
• Current use of hormonal treatment or synthetic steroid therapy.
• Self-reported pregnancy or breastfeeding within the past 3 months.
• Participants currently in an exclusion period following participation in a previous clinical study.
• Individuals under legal protection (guardianship, curatorship, or legal safeguard).
• Inability to provide informed consent (e.g., emergency situation, cognitive or comprehension difficulties).
• Desire for pregnancy within the 3 months following enrollment. The occurrence of pregnancy will not be considered an exclusion criterion; data collected during the menstrual cycle preceding pregnancy may still be analyzed, as it reflects a fertile cycle.

Exposure to potential endocrine disruptors will not be specifically assessed due to their high environmental prevalence and the complexity of their detection.