Because of the complex interplay of events, which are necessary to facilitate the occurrence of the normal menstrual cycle in the female, multiple factors can play roles in producing disorders of the menstrual cycle. Menstrual cycle disorders can be classified as disorders of the process in which eggs are released from the ovaries (ovulation), cycle length, and menstruation, including duration and volume of menstrual blood flow.
Ovulation depends on the occurrence of proper sequencing of events involving a part of the brain called the hypothalamus and the pituitary gland. Any disruption in hypothalamic function can alter hormonal secretion that affects the ovaries. Disruption in the rhythmic secretion of specific hormones important in ovarian function (FSH and LH) will result in anovulation or lack of ovulation. Common disruptions in the hypothalamic secretion include excess weight changes, athletic and psychologic stresses, as well as eating disorders. In addition, pituitary gland lesions such as adenomas (a type of tumor) can alter hormonal events necessary for ovulation to occur. Endocrine system disorders such as chronic an ovulation or polycystic ovary syndrome and thyroid dysfunction may also impact the hormonal changes which affect ovulation. Thus, these conditions can contribute to menstrual cycle disorders.
The interval between menstruations varies from every 21 to 35 days. Even though menstrual cycles vary within this normal range over the reproductive life cycle of a woman, any deviation from her individual pattern often represents a cause for anxiety, and will likely bring her to seek clinical attention. Common diagnoses in this group are oligomenorrhea (menstrual intervals of greater than 35 days), polymenorrhea (intervals of less than 21 days), and amenorrhea (absence of menstruation for more than three normal cycle periods). Causes of these types of abnormal bleeding include underactive thyroid (hypothyroidism), ovulatory dysfunction, pregnancy, premalignant or malignant conditions (some types of tumors), or structural lesions such as polyps. Treatments include correction of hypothyroidism, hormonal contraception, treatment of insulin resistance, progestin (hormone) therapy, and surgery.
The normal duration of menstruation is 4-6 days. Any variation outside of this range represents an abnormality. Common diagnoses in this group are metrorrhagia (irregular periods) and menometrorrhagia (heavy and irregular periods). Usual causes include anatomic lesions such as fibroids and polyps and infections due to cervicitis and endometritis (inflammation of the cervix or lining of the uterus). Often patients will need to undergo an evaluation for bleeding disorders as these may affect the menstrual cycle duration and amount of flow.
Estimates of normal blood flow during menstruation are approximately 20-80 cm3. Ninety percent of flow occurs within the first 48 hours of the onset of menstrual flow. Common diagnoses in this category of disorders include menorrhagia and menometrorrhagia and causes include anatomic lesions such as fibroids, polyps, excessive tissue in the uterine wall (endometrial hyperplasia), neoplasia (tumor) or hypothyroidism, bleeding disorders such as von Willebrand’s disease, or deficiency of blood factors needed for clotting. In addition, any disease causing bone marrow dysfunction or liver disease can contribute to these manifestations. Correction of the underlying cause is usually the basis for treatment.
There are two conditions which merit attention here. One is the condition of midcycle bleeding associated with ovulation. This is due to the rise in the hormones estrogen and progesterone causing shedding of the endometrium (wall of the uterus). It usually lasts for 1-2 days and may be associated with mild cramping. Even though there is no cause for concern, it may cause anxiety in a patient. Although no treatment is usually needed, some patients may receive a hormonal contraceptive method to suppress ovulation. The second condition is called premenstrual tension, which is the cyclic occurrence of symptoms in a specific (luteal) phase of the menstrual cycle. They include somatic complaints (headaches, bloating, or breast tenderness), emotional complaints (anxiety, depression, or irritability), and behavioral complaints (poor concentration, food cravings, or sleep disturbances). Treatment includes suppression of ovulation with medications, exercise, dietary modification, nonsteroidal antiinflammatory drugs (NSAIDs), hormonal contraception, and medical therapy with selective serotonin reuptake inhibitors (SSRIs).