Irregular menstrual bleeding occurs when the time in between periods is longer or shorter than usual, when bleeding occurs that is not a part of the regular cycle or when there is an absence of periods. While the causes of irregular menstrual bleeding can be benign, they also can be symptoms of serious medication conditions. Therefore, any woman experiencing unusual vaginal bleeding or consistently irregular periods should call a doctor.
Hormonal Imbalances
Irregular menstrual bleeding can be caused by having too much or too little of certain hormones, explains the American Congress of Obstetricians and Gynecologists. Hormone imbalances may be caused by many things, including thyroid problems, polycystic ovarian syndrome, certain medications, entering perimenopause or menopause, illness, lifestyle changes (like eating too much or not enough), excessive exercise, and stress. Treatment for hormone imbalances may include taking artificial hormonal medications to regulate the menstrual cycle. In addition, pregnancy can cause hormonal changes that, typically, suppress menstruation.
Fibroids or Polyps
Fibroids are benign growths that form within the uterus, while uterine polyps are growths that develop from the membrane tissue of the uterine lining. These two things are the leading cause of irregular menstrual bleeding in women with normal ovulation patterns, claims the UpToDate medical website.
Cancer
Precancerous conditions and various types of cancer of the female reproductive system may also cause abnormal bleeding that may be mistaken for irregular menstrual bleeding. In some cases, this vaginal bleeding may be the only symptom of the cancer, explains the Hershey Medical Center at Penn State University, which is one of the reasons why reporting unusual vaginal bleeding is so important. Because early detection of cancer can improve the chances of recovery, reporting any irregular vaginal bleeding to a doctor as soon as possible is crucial.
Birth Control Medications
Although, technically, birth control medications do not cause irregular menstrual bleeding, they can cause something called "breakthrough bleeding," which many women may mistake as a period. Typically, this unexpected bleeding only occurs during the first few months of taking the medication and often goes away within four cycles, notes Dr.Spock.com. It also can occur when a woman misses a dose of the birth control medication. However, different birth control medications may affect women differently, so some women may experience breakthrough bleeding for months or, even, years of birth control use. While it is always a good idea to report breakthrough bleeding to a doctor, particularly if it lasts for longer than four months, breakthrough bleeding is not, typically, a cause for concern.
Other Medical Conditions
Other medical conditions can also cause irregular menstrual bleeding. Certain clotting disorders, platelet abnormalities or problems with clotting factors also may cause unusual bleeding from the vagina. Irregular menstrual bleeding can also occur when some other illnesses exist, including hypothyroidism, liver disease or chronic renal disease. A pelvic or vaginal infection, like pelvic inflammatory disease, or a sexually transmitted disease, like chlamydia or gonorrhea, may also be a cause.
