The female menstrual cycle is the orchestrated process, occurring over the period of 28 days on average. This process prepares the body for pregnancy and coordinates the shedding of the uterine lining, also known as menses, if fertilization of an egg does not occur. The menstrual cycle can be divided into two phases, follicular and luteal, which are separated by a critical event known as ovulation. When ovulation does not occur, otherwise known as anovulation, a normal period generally does not result.
Prolonged Cycles or Absent Periods
Ovulation marks the release or expulsion of an egg from its home within the ovary. When this process is altered by conditions such as PCOS and thyroid disease, ovulation often does not occur. Irregular cycles are noted by the Georgia Reproductive Specialists group as a potential symptom of anovulation. The hormonal imbalances that cause this abnormality can cause a normal 28 day cycle to be elongated and even extend beyond the next cycle. This can cause a menstrual bleed not to occur for that month.
Heavy Bleeding
Heavy bleeding is known medically, as menorrhagia. The average woman bleeds for between 4 and 5 days and looses approximately 44 ml of blood, notes the Mayo Clinic. A woman experiencing heavy bleeding can lose 81 ml or more of blood over the same period of time or over an extended period of time. The Mayo Clinic notes that ovarian dysfunction which can be expressed as anovulation can be a cause of heavy bleeding.
Metrorrhagia
Metrorrhagia is characterized by irregular bleeding that occurs most commonly between two consecutive menstrual periods. Metrorrhagia is also referred to as anovulatory bleeding by the Family Practice Notebook. Anovulation leads to a progesterone deficiency, which causes estrogen to go unopposed. The Family Practice Notebook notes that the levels of unopposed estrogens can be high or low, as compared to the absent levels of progesterone. Low levels of unopposed estrogens are noted to result in a lighter and less frequent menstrual flow.
PMS Symptoms
Many women suffer from premenstrual symptoms, otherwise known as PMS. These symptoms vary from woman to woman, but often occur during the few days leading up to and into the menstrual bleed. The Family Practice Notebook notes that the lack of a progesterone rise secondary to the absence of ovulation can cause normal PMS symptoms not to occur. If a woman normally experiences cyclic breast pain or tenderness and premenstrual bloating, when ovulation does not occur, the Family Practice Notebook notes that these events do not transpire.
