[Interrelation between menopausal age and frequency of ovulatory cycles in life]

Menopause develops when excretory (ova-producing) and secretory (hormone-producing) potentialities in the ovary have become exhausted. The present study is an attempt to pursue decisive factors for the life-span of ovarian function with the application of statistical data collected from 30,232 postmenopausal women who were born from 1901 through 1930 in the Hokkaido Prefecture. 1) Although it is often stated that the earlier the menarche the later the menopause, and vice versa, statistical study was made to detect an interrelation between the age of menarche and that of menopause in the cases of which both ages were distinctive. However, the result showed no fixed interrelation there. 2) During a pregnancy and puerperium with natural nutrition, physiological dormancy of ovulation continues for almost one to two years. Studies on the possible existence of interrelation between the frequency of deliveries, which range from zero to ten, and the age of menopause also manifested a negative result. 3) When one of the ovaries is extracted, the remainder functions for the two. Whether or not this exerts influence on the age of menopause was also studied in the cases of unilaterally ovariectomized women to whom the extraction was applied in their twenties and early thirties. The age of menopause in such women proved to be no difference from that in normal cases. In conclusion, it is assumed that the frequency of ovulation does not control the functional life-span of ovary.