​Pathology -Secondary  Amenorrhea
In secondary amenorrhea the female patient has had normal menstruation that has ended for some reason.
The most prevalent reason for secondary amenorrhea is pregnancy, and this should be examined in all patients, even if sexual activity is denied. After pregnancy has been ruled out, TSH and prolactin levels should be evaluated, as hypothyroid conditions and hyperprolactinemia are typical reasons of monthly irregularity or cessation. Other causes include excessively low levels of gonadotropins (pituitary tumor) or abnormally high levels of these same hormones (hypergonadotropic hypogonadism found in ovarian failure). Two common causes of normogonadic secondary amenorrhea include outlet blockage and PCOS. Outflow obstruction may develop owing to uterine scarring from infection, obstructive polyps, or cervical stenosis. PCOS is the most common cause of hyperandrogenic chronic anovulation disease. While the primary etiology of PCOS is uncertain, insulin insensitivity is thought to have a role. Hypothalamic amenorrhea is a disorder linked with anomalies in GnRH secretion and disruption of the hypothalamic–pituitary–ovarian axis. The syndrome is commonly induced by extreme weight loss, activity, or stress and may be found in female athletes with lower than normal percentage of body weight. The mechanism of how stress or weight loss impacts GnRH secretion is unknown. Menses will normally return if a healthy body weight is achieved.