Bleeding after the menstrual period is often a matter of imbalanced hormones, according to the American Academy of Family Physicians. In some cases, birth control, polyps, polycystic ovary syndrome and certain types of cancer alter the body's hormonal balance, according to WebMD.
Hormones play an important role in uterine bleeding. In young women, bleeding often occurs when they don’t ovulate during the menstrual cycle, according to American Academy of Family Physicians. In some cases, estrogen causes the lining of the uterus to overgrow, causing the uterus to shed its lining at odd times. For women in their 40s and 50s, the absence of ovulation or thickening of the lining of the uterus also contribute. However, women in this age group should see a physician when they experience abnormal bleeding.
Besides natural causes, other issues shift a woman’s hormone balance. According to WebMD, birth control pills cause bleeding during the first few months of use in some women. Bleeding may also occur when a woman doesn't take her pill at her normal time. In other cases, conditions such as polycystic ovary syndrome are to blame. A hormonal condition, polycystic ovary syndrome interferes with ovulation, causing bleeding between periods. In more serious but less common cases, conditions such as fibroids, hyperthyroidism and cancer can the cause of bleeding outside of menstruation.
Women who experience unexplained vaginal bleeding should consult a physician to help determine the cause and provide treatment. According to American Academy of Family Physicians, treatments for abnormal bleeding range from birth control to endometrial ablation, which is the removal of the lining of the uterus.