The Sex Organs - The Female Sex Organs

The Menstrual Cycle: The Three Phases of the Menstrual Cycle II

The Three Phases of the Menstrual Cycle
(Seen as beginning with the first day of menstruation)
 

Key: FSH: the follicle somulating hormone; E: estrogen; LH: the luteinizing hormone; P: Progesterone.
Note that the progesterone level rises considerably within twenty four hours after ovulation.