Your menstrual cycle is controlled by hormones. These include estrogen and progesterone. Sometimes there is too much or too little of 1 or both of these hormones. This can cause heavy periods. Or it can cause bleeding between periods. Causes of hormonal imbalance can include:

• Hormonal changes in teens and in people 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 muscle tissue in the uterus. They are not cancer (benign).

• 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 abnormal cells in 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 normally.

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