A woman may become concerned that her body is not functioning properly if she experiences two periods in one month. In many cases, this does not indicate that the woman is unhealthy, though any concerns should be addressed with a doctor. Since most menstrual cycles are around 28 days in length, if a woman starts her period during the first day or two of one month, it is normal to expect the period to start again around the end of the month. Other conditions, such as a hormone imbalance, may also lead to two periods in one month. If the menstrual periods are less than 23 days apart, or if there is severe pain, fever, or extreme clotting, it is important to see a doctor to rule out possible serious health conditions.

For a girl who has recently gone through puberty, it may take a while for menstrual cycles to become regular. In this case, two periods in one month is not usually something to be worried about. The cycles will usually regulate themselves within a matter of months. A gynecologist is a doctor who specializes in female reproductive health and can help the girl determine what is normal during this transitional time in her life.

Hormonal imbalance or thyroid dysfunction may lead to two periods in one month as well. This is particularly common in women who are going through the process of menopause, a signal that a woman's reproductive years are drawing to a close. Hormone therapy is often successful in helping to regulate the cycles if this becomes a common occurrence.

Abnormal masses, such as cysts, polyps, or fibroids, in the uterus also may be responsible for causing two periods in one month. These masses may lead to significant pain as well as disruptions in the normal menstrual cycle. In some cases, medication can help alleviate the symptoms, though surgical intervention is frequently needed.

There are certain situations that should prompt a woman who has had two periods in one month to visit a doctor. If the bleeding is heavy, and there is more pain and cramping than normal, a doctor should be consulted right away. If the patient is passing large, dark clots, and this does not usually happen during her period, a doctor should be consulted. Excess bleeding can lead to a variety of medical conditions, including anemia. For this reason, it is of great importance to report any menstrual changes or concerns to a doctor.