Table 1.

A classification of women in relation to type of menopause and age at menopause.

Type of menopause	Cessation of menses	Cessation of ovarian function	Comments
Surgically induced menopause
Hysterectomy alonea	Abrupt at the time of surgery	Difficult to assess	Current belief is that hysterectomy does not influence ovarian functionb
Hysterectomy plus unilateral oophorectomya	Abrupt at the time of surgery	Difficult to assess	Current belief is that hysterectomy plus unilateral oophorectomy does not influence ovarian functionb
Bilateral oophorectomy with or without hysterectomy	Abrupt at the time of surgery	Abrupt at the time of surgery	Abrupt loss of ovarian function
Natural menopause
Premature menopause, age <40 years	Variable, sometimes with fluctuations	Variable, sometimes with fluctuations	Premature and variable ovarian insufficiencyc
Early menopause, age 40–45 years	Usually gradual and synchronized with cessation of ovarian function	Gradual	Early but usually gradual ovarian insufficiencyc
Normal menopause, age >45 years	Gradual and synchronized with cessation of ovarian function	Gradual	Expected natural ovarian insufficiency

^alt is ambiguous to refer to hysterectomy with one or both ovaries conserved as “surgical menopause”. Because there is cessation of menses, the women are in menopause. However, from an endocrinological perspective, these women will continue to have circulating hormones until the time of cessation of ovarian function.

^blt has been suggested that women who undergo hysterectomy alone or hysterectomy plus removal of one ovary may actually experience an earlier cessation of endocrine function in the remaining ovary or ovaries (Farquhar et al., 2005; Rocca et al., 2007; Phung et al., 2010). Therefore, the current belief of no effect of hysterectomy on ovarian function may be incorrect.

^cDetails about premature or early menopause were reported elsewhere (Shuster et al., 2010).