Follicular or Proliferative Phase

The follicular (or proliferative) phase runs from about day 5 of the cycle until ovulation. In the ovary, gradually rising levels of the gonadotropins FSH and LH stimulate a primary follicle to grow and mature into a full Graafian follicle. At the very same time, in the uterus, the endometrium — freshly shed during menstruation — regenerates and thickens through active cell proliferation. This dual naming reflects the dual action: the phase is 'follicular' from the ovary's point of view and 'proliferative' from the uterus's, but both changes are driven by the same rising FSH/LH signal, with …