Related Experiment Video
Updated: Jul 15, 2025

Rodent Estrous Cycle Monitoring Utilizing Vaginal Lavage: No Such Thing As a Normal Cycle
Published on: August 30, 2021
Establishing a Gold Standard for Quantitative Menstrual Cycle Monitoring
Thomas Bouchard1,2, Paul Yong1, Patricia Doyle-Baker3
1Department of Obstetrics & Gynecology, University of British Columbia, Vancouver, BC V6Z 2K8, Canada.
Abstract:
Background and Objectives: The Quantum Menstrual Health Monitoring Study will measure four key reproductive hormones in the urine (follicle-stimulating hormone, FSH; estrone-3-glucuronide, E13G; luteinizing hormone, LH; and pregnanediol glucuronide, PDG) to characterize patterns that predict and confirm ovulation, referenced to serum hormones and the gold standard of the ultrasound day of ovulation in participants with regular cycles. These normal cycles will provide a reference for comparison to irregular cycles in subjects with polycystic ovarian syndrome (PCOS) and athletes. Materials and Methods: Participants will track their menstrual cycles for 3 months and be provided with an at-home urine hormone monitor (Mira monitor) to predict ovulation. The day of ovulation will be confirmed with serial ultrasounds completed in a community clinic. Urine results will be compared to serum hormone values. Other markers of menstrual health, such as bleeding patterns and temperature changes, will be determined using a customized app. Three groups will be recruited. Group 1 will include those with consistent regular cycle lengths (between 24-38 days), and will be compared to two groups with irregular cycle lengths (with increased cycle length variability and longer cycles). Group 2 will include those with polycystic ovarian syndrome (PCOS) with irregular cycles and Group 3 will include individuals participating in high levels of exercise with irregular cycles. Hypothesis: The Mira monitor quantitative urine hormone pattern will accurately correlate with serum hormonal levels and will predict (with LH) and confirm (with PDG) the ultrasound day of ovulation in those with regular cycles as well as those with irregular cycles. Rationale: Once the ultrasound validation is complete, tools like the Mira monitor with a customized app may become a new standard for at-home and remote clinical monitoring of the menstrual cycle without having to use labor-intensive follicular-tracking ultrasound or follow serum hormone changes. Conclusions: Precision monitoring of the menstrual cycle is expected to impact individuals who want to increase their menstrual health literacy and guide decisions about fertility.
Related Concept Videos
Hormonal Regulation of the Menstrual Cycle
At puberty, GnRH begins a pulsatile release pattern, which triggers the anterior pituitary gland to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The frequency and amplitude of GnRH pulses vary across the menstrual cycle, with faster pulses favoring LH release and slower pulses favoring FSH...
The Menstrual Cycle
The menstrual phase occurs from days 1 to 5 and involves the shedding of the stratum functionalis, as a...
Ovarian Cycle
Hormonal Control of the Ovarian Cycle
Before puberty, the hypothalamus releases GnRH in a low frequency, low amplitude pulsatile manner. This along with the immature hypothalamic-pituitary-gonadal axis activity, results in low estrogen levels and the absence of a fully functional ovarian cycle. At puberty, GnRH secretion increases in both frequency and...

