The effect of age upon the pattern of the menstrual cycle
Collett, M.E.; Wertenberger, G.E.; Fiske, V.M.
Fertility and Sterility 5(5): 437-448
1954
ISSN/ISBN: 0015-0282 PMID: 13200587 DOI: 10.1016/s0015-0282(16)31742-3Document Number: 517296
An analysis is presented of B.T. or BMR curves of 302 cycles from 146 persons between 17-50 years of age, as to cycle length, duration of menses, day of ovulation, and length and character of the luteal phase. In 'all these categories variability is least at 25-34 years and increases in the younger and older groups. Anovulatory cycles are relatively infrequent at 25-34 years (2.9%) but occur in 9.8-30.8% of the cycles of both younger and older subjects. Ovulation generally occurs between day 10 and day 18; after 35 and until the appearance of long cycles at the menopause it tends to come earlier. The luteal phase generally varies between 12-16 days, but sometimes varies more extremely (4-26 days). The luteal temperature rise occurs rapidly in young subjects, but the maximum rise is greatest at 25-34 years. Variability both in the day of ovulation and in length of the luteal phase may be considerable even in the same person.