Editing Menstrual cycle (section)

==== Luteal phase ====
{{main|Luteal phase}}
Lasting about 14 days,<ref name="Reed2018" /> the luteal phase is the final phase of the ovarian cycle and it corresponds to the secretory phase of the uterine cycle. During the luteal phase, the pituitary hormones FSH and LH cause the remaining parts of the dominant follicle to transform into the corpus luteum, which produces progesterone.{{sfn|Johnson|2007|page=91}}{{efn|In the corpus luteum, [[cholesterol side-chain cleavage enzyme]] converts [[cholesterol]] to [[pregnenolone]], which is converted to progesterone.<ref name="pmid22201776">{{cite journal |vauthors=King SR, LaVoie HA |title=Gonadal transactivation of STARD1, CYP11A1 and HSD3B |journal=Frontiers in Bioscience (Landmark Edition) |volume=17 |issue= 3|pages=824–846 |date=January 2012 |pmid=22201776 |doi=10.2741/3959 |doi-access=free }}</ref>}} The increased progesterone starts to induce the production of estrogen. The hormones produced by the corpus luteum also suppress production of the FSH and LH that the corpus luteum needs to maintain itself. The level of FSH and LH fall quickly, and the corpus luteum atrophies.{{sfn | Ugwumadu | 2014 | p=117}} Falling levels of progesterone trigger menstruation and the beginning of the next cycle. For an individual woman, the follicular phase often varies in length from cycle to cycle; by contrast, the length of her luteal phase will be fairly consistent from cycle to cycle at 10 to 16 days (average 14 days).{{sfn | Tortora | 2017 | pp=942–946}}