Assessing menstrual cycles with urinary hormone assays.

Area of Science:

• Reproductive Endocrinology
• Women's Health Research
• Biomarker Assay Development

Background:

• The Study of Women's Health Across the Nation (SWAN) is a multiethnic cohort study focusing on middle-aged women.
• Assessing hormonal changes during the menstrual cycle is crucial for understanding reproductive aging.
• Existing methods for analyzing longitudinal hormonal data require validation for large-scale application.

Purpose of the Study:

• To evaluate the performance of algorithms for identifying normal menstrual cycle features in reproductively aging women.
• To validate objective methods for analyzing urinary gonadotropins and sex steroid metabolites.
• To assess the reliability of algorithms in determining luteal status and the timing of ovulation.

Main Methods:

• Urinary luteinizing hormone (LH), follicle-stimulating hormone (FSH), estrone conjugates (E1c), and pregnanediol glucuronide (Pdg) were measured.
• Algorithms were developed based on existing methods and compared against trained observer ratings of 396 menstrual cycles.
• Performance was evaluated for identifying luteal activity and the day of the luteal transition.

Main Results:

• A pregnanediol glucuronide (Pdg) threshold algorithm demonstrated high agreement (320/328 cycles) in identifying evidence of luteal activity (ELA).
• Algorithms evaluating the ratio of estrone conjugates (E1c) to Pdg achieved 85-92% agreement for the day of luteal transition.
• Minimal improvement in agreement was observed with additional algorithmic conditions.

Conclusions:

• Reliable, objective, and simple methods using urinary hormone assays can evaluate the probability and timing of ovulation in early perimenopausal women.
• These validated algorithms are suitable for serial analysis of large, longitudinal hormonal databases.
• The findings support the use of these methods in reproductive aging research.