Editing Menarche (section)

===Relation to fertility===
For most girls, menarche does not mean that [[ovulation]] has occurred. In post-menarchal girls, about 80% of the cycles are [[anovulatory]] in the first year after menarche, 50% in the third, and 10% in the sixth year.<ref name="Apter D 1980 107–20">{{cite journal | vauthors = Apter D | title = Serum steroids and pituitary hormones in female puberty: a partly longitudinal study | journal = Clinical Endocrinology | volume = 12 | issue = 2 | pages = 107–20 | date = February 1980 | pmid = 6249519 | doi = 10.1111/j.1365-2265.1980.tb02125.x | s2cid = 19913395 }}</ref> Regular ovulation is usually indicated by predictable and consistent intervals between menses, and predictable and consistent patterns of flow (e.g., heaviness or cramping). Continuing ovulation typically requires a [[body fat percentage]] of at least 22%.<ref name=hr/>

Not every girl follows the typical pattern. Some girls ovulate prior to their first [[menstruation]]. Although unlikely, it is possible for a girl who has engaged in [[sexual intercourse]] shortly before her menarche to [[Conception (biology)|conceive]] and become [[pregnancy|pregnant]] (delaying her menarche until after the end of her pregnancy, if she carries to full term).

Younger age of menarche is not correlated with a younger age of first sexual intercourse.<ref>{{cite journal | vauthors = Marino JL, Skinner SR, Doherty DA, Rosenthal SL, Cooper Robbins SC, Cannon J, Hickey M | title = Age at menarche and age at first sexual intercourse: a prospective cohort study | journal = Pediatrics | volume = 132 | issue = 6 | pages = 1028–36 | date = December 2013 | pmid = 24218473 | doi = 10.1542/peds.2012-3634 | hdl = 11343/219824 | s2cid = 1930969 | url = http://minerva-access.unimelb.edu.au/bitstream/11343/219824/4/AAM_and_sexual_debut_R2.pdf | hdl-access = free }}</ref>