Change of Ovarian Function with Age

Abstract

It is recognized statistically and clinically that the lowering of female fertility appears with age. During the climacteric, there is frequent to happen ovarian dysfunction, such as menstrual disorders or dysfunctional uterine bleeding, and the climacteric symptoms as somatic and psychic changes. These clinical changes suggest the lowering of ovarian function according to aging. However, from the aspects of urinary estrogen level, the strinkig decrease of the level is not observed before menopause. In postmenopausal women, it is low value, as general, but the higher levels are revealed in some cases. In any event, very low level as in childhood is not observed.From the recording of 18,213 menstrual cycles, it is observed that the length of cycle shortens with age. Basal temperature records of 3,000 ovulatory cycles shows that the average length of follicular phase shortens with age, although that of luteal phase does not change in women of over 20 years old. So it is clear that the shortening of menstrual cycle is a result of shortening of follicular phase. The shortening of period and decrease of flow are also observed in women of over 35 years old, and the increase of inadequate luteal phase or anovulatory cycle especially in women of over 40 years old.Lowering of ovarian function with age does not mean only the decrease of estrogen secretion, but irregularity of ovarian cycle function that induces umblance of estrogen and progesterone secretion. The fact that the endometrial hyperplasia induced by prolonged or profuse estrogen action frequently takes place in climacteric women supports the abovementioned opinion.Urinary total gonadotrophins increase in some cases of menopausal women, and rise remarkably in postmenopausal women. Follicle stimulating hormone is within normal value or a little higher before menopause, and rises usually in postmenopausal women. Then, in more than five years after menopause, FSH tends to return to normal range. LH increases to ovulatory level in postmenopausal women. Urinary 17KS value increases during menopause.With age, ovarian size becomes smaller, and following histological changes appear : appearance of germinal inclusion cyst or corpus albicans cyst, disappearance of corpus luteum, decrease of atretic follicle, disappearance of graafian follicle, decrease of a number of a internal theca cell and interstitial cell, accumulation of Sudan IV strain in ovarian cortex, and increase of Sudan IV strain in wand of ovarian vessels. From these phenomenon, it is supposed that structual ovarian atrophy begins between 35 and 40 years old. Especially blood vessels in ovary change remarkably after 35 years old. So, the change of ovarian vessel is suggested to play an important role to lowering of ovarian function.