Menstrual cycle disorders can be divided into two categories: amenorrhea, the absence of menstruation, and oligomenorrhea, infrequent or irregular menstruation. Primary amenorrhea is a condition in which menstruation has never occurred. An example is Turner's syndrome, also called gonadal dysgenesis, a congenital abnormality caused by a nondisjunction of one of the X chromosomes, resulting in a 45 X0 chromosomal karyotype. Because the two X chromosomes are necessary for normal ovarian development, women with this condition have rudimentary gonads and do not have a normal puberty. Because of ovarian steroid deficiency (lack of estrogen), secondary sex characteristics remain prepubertal, and plasma LH and FSH are elevated. Other abnormalities include short stature, a webbed neck, a coarctation of the aorta, and renal disorders.
Another congenital form of primary amenorrhea is hy-pogonadotropism with anosmia, similar to Kallmann's syn
f TABLE 38.3
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