A menstrual cycle is defined by the period marked by the first day of one menstrual bleed and the first day of the next menstrual bleed. The length of an average menstrual bleed is 28 days, however, normal variations among women allow for cycles of 24 to 34 days in length to still be considered normal. Greater than 35 days is considered a prolonged cycle and an example of abnormal bleeding, according to the National Institutes of Health.
PCOS
Polycystic ovarian syndrome, also known as Stein-Leventhal Syndrome, is a condition characterized by variations of menstruation, including lack of ovulation, prolonged or even absent cycles, abnormal bleeding, insulin resistance or pre-diabetes, and excess androgen or testosterone-like hormones.
A normal menstrual cycle will call for a race among the egg-occupied follicles until one gains full maturity. The competing follicles will produce estrogen to encourage this race. The increased estrogen will lead to an increase in another hormone from the brain, Leutinizing Hormone, which will give the winning egg the required jolt it needs to burst through the ovary wall. This process is known as ovulation.
Women with PCOS, according to the U.S. Department of Health and Human Services, never fully mature any follicles and follicles remain as water-filled cysts. Lacking the development of a mature egg compromises ovulation and inhibits the resulting rise in progesterone. HHS notes that a menstrual cycle will be irregular or prolonged in the absence of progesterone.
Stress
Stress can result from psychological and emotional influences as well as during physiological occurrences like illness, infection or a severe trauma. Stress also influences the hormones involved in coordinating a normal menstrual cycle. The Women's Health Resource Center at Rice University notes that stress can be a cause of anovulation. If ovulation does not occur, progesterone and a period generally do not result. The disturbed hormonal balance that results is noted by the Resource Center, as a reason for a late or skipped period and thus a prolonged cycle.
Perimenopause
Perimenopause describes the years surrounding the one-year anniversary of the last menstrual bleed. The anniversary date is often denoted as menopause, but the years leading up to the landmark can be very confusing for women and result in numerous changes in the menstrual cycle. A pamphlet by the American Congress of Obstetricians and Gynecologists notes the normal cyclic hormonal production and cycle of ovulation shifts during periomenopause can lead to cycles that may last longer than normal. The ACOG notes that in other women, the changes of perimenopause can lead to shorter cycles and increases or decreases in bleeding in years and months leading up to menopause.
Thyroid Disease
The thyroid controls the body's metabolism or collective breakdown of calories to be used by the cells for energy. Dysfunction of the thyroid gland, either in hyperproduction or hypoproduction of the hormones, directly influences reproductive hormones like estrogen and progesterone. The Georgia Reproductive Specialists notes that a low functioning thyroid can lead to an increase in prolactin stimulation and prolonged estrogen exposure. The prolonged estrogen stimulation will impact the maturity of the follicles and inhibit ovulation. These events, note the specialists group, can lead to prolonged menstrual cycles as well as changes in bleeding quantity.
References
- National Institutes of Health--Medline Plus: Menstrual periods -- heavy, prolonged or irregular
- U.S. Department of Health & Human Services: Polycystic Ovary Syndrome
- Rice University--Women's Resource Center: "Ask Anything"
- American Congress of Obstetricians and Gynecologists: Perimenopausal Bleeding and Bleeding After Menopause
- Georgia Reproductive Specialists--Miracle Babies: Finding Out Why Your Periods Are Abnormal.
