Your menstrual cycle is controlled by hormones. The hormones include estrogen and progesterone. Sometimes there is too much or too little of one or both of these hormones, causing an imbalance. This can cause heavy periods. Or it can cause bleeding between periods. Causes of hormonal imbalance can include:

• Hormonal changes in teens and in women nearing menopause

• Diabetes, thyroid disease, or other medical problems

• Obesity

• Stress

• Strenuous exercise

• Anorexia, an eating disorder

• Pregnancy

There are different kinds of uterine growths. These include:

• Fibroids. These are round knots of noncancer (benign) muscle tissue in the uterus.

• Polyps. These are soft tissue growths in the uterine lining. They often extend into the uterus.

• Adenomyosis. This is when the uterine lining grows into the muscle wall.

• Hyperplasia. This is when the uterine lining gets too thick or grows too much.

• Endometrial cancer. This is uncontrolled growth of part of the uterine lining.

There are other causes of uterine bleeding. These include:

• IUD (intrauterine device). This is a method of birth control. Some IUDs contain hormones.

• Bleeding disorders. This is when the blood can't clot properly.

Your healthcare provider can help diagnose the cause of your bleeding problem. He or she will work with you to plan treatment as needed.