Question

What is the source of the hormones that, when suddenly absent, are directly responsible for the onset of menstruation?.

Answer 1

Therefore, the pituitary secretes FSH and LH, a process which actually begins before the onset of menses. These hormones, in turn, stimulate the growth of several ovarian follicles (each containing one egg). The number of follicles in the "cohort" of developing follicles each month is unique to each individual.