Which is not primary amenorrhea?

Ans. is a, i.e. Sheehan's syndromeRef: Shaw 14th/ed, p256-257* Kallmann's sydnrome is due to hypothalamic dysfunction characterized by a deficiency of gonadotropin releasing hormone (GnRH) causing a hypogonadotrophic hypogonadism. This is associated with anosmia. It can occasionally be associated with optic problems, such as color blindness or optic atrophy, nerve deafness, cleft palate, cryptorchidism, renal agenesis, and mirror movement disorder.* MRKH syndrome, also known as Mullerian agenesis is due to anatomical absence of uterus. This is the second most common cause of primary amenorrhea.* Turner's syndrome is a type of gonadal dysgenesis and is overall the most common cause of primary amenorhea* Sheehan's syndrome is postpartum pituitary necrosis. It leads to secondary amenorrhea and not primary amenorrhea.