The follicular phase of the menstrual cycle involves the hourly release of
gonadotropin-releasing hormone, which binds to receptors on the gonadotropes. This results in
the secretion of follicle stimulating hormone and luteinizing hormone in hourly pulses that
regulate follicular growth. At midcycle, rapidly rising estradiol from the dominant follicle
and a small rise in progesterone lead to a gonadotrophic surge. An increase in the amplitude
of Luteinizing hormone and Follicle stimulating hormone pulses initiates oocyte maturity and
triggers ovulation approximately