Anovulatory cycle
While the normal menstrual cycle in the human typically lasts 4 weeks (28 days, range 24–35 days) and consists of a follicular phase, ovulation, and a luteal phase, followed by either menstruation or pregnancy, the anovulatory cycle has cycle
lengths of varying degrees. In many circumstances, menstrual intervals are prolonged exceeding 35 days leading to oligomenorrhea (cycle >35 – 180 days interval), or even longer, amenorrhea. In other cases, menstruation may be fairly regular (eumenorrhea), or more frequent (intervals < 21 days), or there may be a loss of menstrual pattern (menorrhagia, dysfunctional uterine bleeding).
Menstruation
There is debate among medical researchers about the potential long-term impacts of these practices upon female health. Some researchers point to the fact that historically, females have had far fewer menstrual periods throughout their lifetimes, a result of shorter life expectancies, as well as a greater length of time spent pregnant or breast-feeding, which reduced the number of periods experienced by females. These researchers believe that the higher number of menstrual periods by females in modern societies may have a negative impact upon their health. On the other hand, some researchers believe there is a greater potential for negative impacts from exposing females perhaps unnecessarily to regular low doses of synthetic hormones over their reproductive years.