In many circumstances, menstrual intervals are prolonged, reaching 35–180 days (oligomenorrhea) or even longer (amenorrhea).
In other cases, menstruation may be fairly regular (eumenorrhea), more frequent (intervals of less than 21 days) or there may be a loss of menstrual pattern (menorrhagia, dysfunctional uterine bleeding).
Normal menstrual bleeding in the ovulatory cycle is a result of a decline in progesterone due to the demise of the corpus luteum.
Common causes are: With excessive or prolonged bleeding the diagnosis has to be made by a physician on a speedy basis.
In patients who do not want to get pregnant anovulation can be managed with the use of cyclic progesterone or progestin supplementation or use of hormonal contraception.