Menstrual cycle and the lining of the uterus thickens. Follicles in the ovary begin developing under the influence of a complex interplay of hormones, and after several days one or occasionally two become dominant (non-dominant follicles shrink and die). Approximately mid-cycle, 24–36 hours after the luteinizing hormone (LH) surges, the dominant follicle releases an ovocyte, in an event called ovulation. After ovulation, the ovocyte only lives for 24 hours or less without fertilization while the remains of the dominant follicle in the ovary become a corpus luteum; this body has a primary function of producing large amounts of progesterone. Under the influence
Topical progesterone of tissue exposure to progesterone with this route of administration. These findings provide a possible explanation for how some studies found antiproliferative and atrophic changes in the endometrium with topical progesterone. However, elevated levels of progesterone in the endometrium with topical progesterone have not yet been demonstrated. Concern has been raised regarding topical progesterone in that the effects of such supraphysiological levels of progesterone in tissues are unknown and hence the potential for harmful effects has not been ruled out. Salivary monitoring of progesterone levels in women using topical progesterone and adjustment of dosage as necessary has been suggested as