Ovulatory Phase

The ovulatory phase falls around the middle of the cycle, close to day 14, when both FSH and LH reach their peak levels for the cycle. LH in particular shows a sharp, well-defined spike at this point, known as the LH surge, and it is this surge that directly triggers ovulation: it causes the mature Graafian follicle to rupture and release the enclosed secondary oocyte from the ovary wall out into the peritoneal cavity, where the fallopian tube's fimbriae are positioned to sweep it up. Ovulation is therefore tied specifically to this LH-surge eve …