Insights in Endocervical Mucus Secretion

This study will enroll participants and obtain biological samples at 4 time points. The study will begin on the first day of menstruation following enrollment. Patients will monitor for peri-ovulation using an ovulation test that monitors for urinary metabolites for luteinizing hormone (LH). At the midluteal time point for sampling (days 6-9 after "high fertility" on ovulation test) subjects will begin taking an oral gonadotropin-releasing hormone antagonist (gnRH) (relugolix) for 10 days. Samples of whole blood, endocervical mucus, endocervical biopsy, and vaginal swab will be collected during the early follicular phase (3-5 days following the start of menstruation), peri-ovulation (9-14 days following the start of menstruation based on estriol glucuronide (E3G) urinary metabolite), mid-luteal (6-9 days following mid-cycle draw), and upon stoppage of relugolix (9-11 days following relugolix initiation).