Menstrual cycle irregularities are not unusual, although the causes of abnormal bleeding may vary by age. For example, cancers are more likely to trigger irregular bleeding in postmenopausal women than in younger women, while pregnancy-related bleeding is more common among reproductive-age women.

After age 50, postmenopausal bleeding may occur and should be evaluated by a healthcare professional. For women ages 15–49, there are three abnormal bleeding patterns, and each has specific causes. Be sure to exclude pregnancy before considering other reasons.

The three most common bleeding patterns are:

Heavy menstrual bleeding

This is when the cycles are regular but the bleeding is heavy or prolonged. Bleeding is considered heavy if you have to change a pad or tampon every one to two or hours because it’s completely soaked or you're passing large clots. Bleeding is considered prolonged if it lasts more than eight days.

The most common causes of heavy menstrual bleeding are:

• Fibroids
  A fibroid is an abnormal growth of the muscles of the uterus. Fibroids are common, with some studies showing that approximately 80% of women will have fibroids during their lifetime, although not all will experience symptoms.
• Adenomyosis
  This condition occurs when the cells that line the inner walls of the uterus begin invading the muscles of the uterus. This condition often causes heavy and painful periods.
• Bleeding disorder
  This condition affects the way the blood clots. A bleeding disorder is likely if heavy or prolonged menses began at menarche, or first menstruation; there is a family history of bleeding issues;  there are signs of a bleeding problem, such as easy bruising; or if taking medications that can prevent usual clotting.

Intermenstrual bleeding

This refers to vaginal bleeding at any time during the menstrual cycle other than during normal menstruation.

The most common causes of intermenstrual bleeding include:

• Cancer or pre-cancer
  Cancer or pre-cancer growth on the uterus or cervix can cause intermenstrual bleeding. This is more likely if a woman has had previous abnormal Pap smears or if there are other risk factors, such as obesity, family history of uterine cancer or bleeding that has been going on for a long time without evaluation.
• Cesarean scar defect
  Two-thirds of women who had a C-section may have a cesarean scar defect. Approximately one-third of women with this condition experience bleeding that starts just after the end of their regular menstruation.
• Contraceptive methods
  Many contraceptive methods can cause intermenstrual and irregular bleeding, especially in the first few months after starting the method.
• Pelvic infections
  Intermenstrual bleeding can be a sign of an infection in the uterus or on the cervix. This usually causes pelvic pain or increased vaginal discharge in addition to bleeding. Pelvic infections are more common in women who have been exposed to sexually transmitted infections, recently gave birth or had surgery on their uterus or cervix.
• Polyps
  A polyp is an overgrowth of cells around a small blood vessel inside the uterus or on the cervix.

Irregular bleeding

This is when a woman goes through phases of no bleeding that may last two or more months and other phases with either spotting or episodes of heavy bleeding. Irregular bleeding most often is related to abnormal ovulation or what's known as polycystic ovarian syndrome.

All women with menstrual irregularities should see a healthcare professional for an evaluation to uncover the cause of their problem. The evaluation considers a woman's bleeding pattern and medical history, and includes a physical and pelvic exam. Additional testing based on the evaluation could include a urine pregnancy test, hormonal testing, an ultrasound, a biopsy called endometrial biopsy and a Pap smear. Once the cause of the bleeding is determined, a treatment plan can be developed to manage the problematic bleeding pattern.

For women experiencing menstrual cycle irregularities, help is available so you don’t have to suffer through another painful period from the JMH Women's Health team.

Johnson Memorial Health is a member of the Mayo Clinic Care Network — a select group of carefully vetted, independent healthcare organizations with special access to Mayo Clinic knowledge, resources and expertise.