Menstrual Cycle - Cycle Abnormalities and Disorders

Cycle Abnormalities and Disorders

Infrequent or irregular ovulation is called oligoovulation. The absence of ovulation is called anovulation. Normal menstrual flow can occur without ovulation preceding it: an anovulatory cycle. In some cycles, follicular development may start but not be completed; nevertheless, estrogens will form and will stimulate the uterine lining. Anovulatory flow resulting from a very thick endometrium caused by prolonged, continued high estrogen levels is called estrogen breakthrough bleeding. Anovulatory bleeding triggered by a sudden drop in estrogen levels is called changes. Anovulatory cycles commonly occur before menopause (perimenopause) and in women with polycystic ovary syndrome.

Very little flow (less than 10 ml) is called hypomenorrhea. Regular cycles with intervals of 21 days or fewer are polymenorrhea; frequent but irregular menstruation is known as metrorrhagia. Sudden heavy flows or amounts greater than 80 ml are termed menorrhagia. Heavy menstruation that occurs frequently and irregularly is menometrorrhagia. The term for cycles with intervals exceeding 35 days is oligomenorrhea. Amenorrhea refers to more than three to six months without menses (while not being pregnant) during a woman's reproductive years.

George Preti, an organic chemist at the Monell Chemical Senses Center in Philadelphia and Winnefred Cutler of the University of Pennsylvania's psychology department, discovered that women with irregular They hypothesized that the only explanation was that underarms contain pheromones, as there was no other explanation for the effects, which mirrored how pheromones affect other mammals.