What is abnormal menstruation?

Most women have menstrual periods that last four to seven days. A woman's period usually occurs every 28 days, but normal menstrual cycles can range from 21 days to 35 days.

Examples of menstrual problems include:

  • Periods that occur less than 21 days or more than 35 days apart
  • Missing three or more periods in a row
  • Menstrual flow that is much heavier or lighter than usual
  • Periods that last longer than seven days
  • Periods that are accompanied by pain, cramping, nausea, or vomiting
  • Bleeding or spotting that happens between periods, after menopause, or following sex

Examples of abnormal menstruation include the following:

  • Amenorrhea is a condition in which a woman’s periods have stopped completely. The absence of a period for 90 days or more is considered abnormal unless a woman is pregnant, breastfeeding, or going through menopause (which generally occurs for women between ages 45 and 55). Young women who haven't started menstruating by age 15 or 16 or within three years after their breasts begin to develop are also considered to have amenorrhea.
  • Oligomenorrhea refers to periods that occur infrequently.
  • Dysmenorrhea refers to painful periods and severe menstrual cramps. Some discomfort during the cycle is normal for most women.
  • Abnormal uterine bleeding may apply to a variety of menstrual irregularities, including: a heavier menstrual flow; a period that lasts longer than seven days; or bleeding or spotting between periods, after sex, or after menopause.

What causes abnormal menstruation (periods)?

There are many causes of abnormal periods, ranging from stress to more serious underlying medical conditions:

  • Stress and lifestyle factors. Gaining or losing a significant amount of weight, dieting, changes in exercise routines, travel, illness, or other disruptions in a woman's daily routine can have an impact on her menstrual cycle.
  • Birth control pills. Most birth control pills contain a combination of the hormones estrogen and progestin (some contain progestin alone). The pills prevent pregnancy by keeping the ovaries from releasing eggs. Going on or off birth control pills can affect menstruation. Some women have irregular or missed periods for up to six months after discontinuing birth control pills. This is an important consideration when you are planning on conception and becoming pregnant. Women who take birth control pills that contain progestin only may have bleeding between periods.
  • Uterine polyps or fibroids. Uterine polyps are small benign (noncancerous) growths in the lining of the uterus. Uterine fibroids are tumors that attach to the wall of the uterus. There may be one or several fibroids that range from as small as an apple seed to the size of a grapefruit. These tumors are usually benign, but they may cause heavy bleeding and pain during periods. If the fibroids are large, they might put pressure on the bladder or rectum, causing discomfort.
  • Endometriosis. The endometrial tissue that lines the uterus breaks down every month and is discharged with the menstrual flow. Endometriosis occurs when the endometrial tissue starts to grow outside the uterus. Often, the endometrial tissue attaches itself to the ovaries or fallopian tubes; it sometimes grows on the intestines or other organs in the lower digestive tract and in the area between your rectum and uterus. Endometriosis may cause abnormal bleeding, cramps or pain before and during periods, and painful intercourse.
  • Pelvic inflammatory disease. Pelvic inflammatory disease (PID) is a bacterial infection that affects the female reproductive system. Bacteria may enter the vagina via sexual contact and then spread to the uterus and upper genital tract. Bacteria might also enter the reproductive tract via gynecologic procedures or through childbirth, miscarriage, or abortion. Symptoms of PID include a heavy vaginal discharge with an unpleasant odor, irregular periods, pain in the pelvic and lower abdominal areas, fever, nausea, vomiting, or diarrhea.
  • Polycystic ovary syndrome. In polycystic ovary syndrome (PCOS), the ovaries make large amounts of androgens, which are male hormones. Small fluid-filled sacs (cysts) may form in the ovaries. These can often been seen on ultrasound. The hormonal changes can prevent eggs from maturing, and so ovulation may not take place consistently. Sometimes a woman with polycystic ovary syndrome will have irregular periods or stop menstruating completely. In addition, the condition is associated with obesity, infertility, and hirsutism (excessive hair growth and acne). This condition may be caused by a hormonal imbalance, although the exact cause is unknown. Treatment of PCOS depends on whether a woman desires pregnancy. If pregnancy is not a goal, then weight loss, oral contraceptive pills, and the medication Metformin® (an insulin sensitizer used in diabetes) can regulate a woman’s cycles. If pregnancy is desired, ovulation-stimulating medications can be tried.
  • Premature ovarian insufficiency. This condition occurs in women under age 40 whose ovaries do not function normally. The menstrual cycle stops, similar to menopause. This can occur in patients who are being treated for cancer with chemotherapy and radiation, or if you have a family history of premature ovarian insufficiency or certain chromosomal abnormalities. If this condition occurs, see your physician.

Other causes of abnormal menstruation include:

  • Uterine cancer or cervical cancer
  • Medications, such as steroids or anticoagulant drugs (blood thinners)
  • Medical conditions, such as bleeding disorders, an under- or overactive thyroid gland, or pituitary disorders that affect hormonal balance
  • Complications associated with pregnancy, including miscarriage or an ectopic pregnancy (the fertilized egg is implanted outside the uterus; for example, within the fallopian tube)