Amenorrhea is defined either as failure of menarche by age 16, regardless of the presence or absence of secondary sexual characteristics, or as the absence of menstruation for 6 months in a women with previous periodic menses. Amenorrhea can be categorized into two types -
Primary Amenorrhea - Amenorrhea in a women who has never menstruated.
Secondary Amenorrhea - It is the cessation of menses.
Causes of Amenorrhea
Because some disorders can cause both primary and secondary Amenorrhea, we prefer a functional classification based on the nature of the underlying defect, namely, anatomic defects of the outflow tract (uterus, cervix, or vagina), ovarian failure and chronic anovolution.
Anatomic defects for Amenorrhea
Anatomic defects of the outflow tract include congential defects of vagina, important hymen, transverse vaginal septa, cervical stenosis, intrauterine adhesions, absence of the vagina or uterus and urine maldevelopment. The diagnosis of an anatomic defect is usually made by physical examination but may be confirmed by demonstrating failure of bleeding following administration of estrogen plus a progestogen or hysteroscopy may be helpful in defining the defect.
Women with chronic anovulation fail to ovulate spontaneously but have the capability of oveulating with appropriate therapy. In some women with chronic anovulation, total estrogen production is adequate, but it is not secreted in a cyclic fashion. In others, estrogen production is deficient.