- When you are not expecting your menstrual period.
- When your menstrual flow is lighter or heavier than what is normal for you.
- At a time in life when it is not expected, such as before age 9, when you are pregnant, or after menopause.
Abnormal vaginal bleeding has many possible causes. By itself, it does not necessarily indicate a serious condition.
- Because bleeding can mean a problem with the pregnancy, possible pregnancy should always be considered in a woman of childbearing age.
- Spotting to minimal bleeding may be normal. But any bleeding during pregnancy needs to be evaluated by your doctor.
- Heavy vaginal bleeding or bleeding that occurs before 12 weeks may mean a serious problem, including an ectopic pregnancy or miscarriage.
- Heavy vaginal bleeding or bleeding that occurs after 12 weeks also may mean a serious problem, such as placenta previa.
- Ovulation can cause mid-cycle bleeding.
- Polycystic ovary syndrome (PCOS) is a hormone imbalance that interferes with normal ovulation and can cause abnormal bleeding.
- Medicines, such as birth control pills, sometimes cause abnormal vaginal bleeding. You may have minor bleeding between periods during the first few months if you have recently started using birth control pills. You also may have bleeding if you do not take your pills at a regular time each day.
- An intrauterine device (IUD) also may increase your chances of spotting or heavy periods.
- Infection of the pelvic organs (vagina, cervix, uterus, fallopian tubes, or ovaries) may cause vaginal bleeding, especially after intercourse. Sexually transmitted infections (STIs) are often the cause of infections.
- Sexually Transmitted Infections.
- Pelvic inflammatory disease (PID) causes inflammation or infection of the uterus, fallopian tubes, or ovaries, which can cause abnormal bleeding.
Other common causes of abnormal vaginal bleeding that may be more serious include:
- Sexual abuse.
- An object in the vagina.
- Uterine fibroids, which are a common cause of heavy periods. For more information, see the topic Uterine Fibroids.
- Structural problems, such as urethral prolapse or polyps.
- Cancer of the cervix, uterus, ovaries, or vagina.
- Extreme emotional stress and excessive exercise. But excessive exercise more frequently causes an absence of menstruation (amenorrhea).
- Other diseases, such as hyperthyroidism or diabetes.
Heavy bleeding during the first few weeks after delivery (postpartum) or after an abortion may occur because the uterus has not contracted to the pre pregnancy size or because fetal tissue remains in the uterus (retained products of conception).
If you are age 40 or older, abnormal vaginal bleeding may mean that you are entering perimenopause. In a woman who has not had a menstrual period for 12 months, vaginal bleeding is always abnormal and should be discussed with your doctor.
Treatment of abnormal vaginal bleeding depends on the cause of the bleeding.