Many things can cause irregular periods. Changes in your body's level of the hormones estrogen and progesterone can disrupt the normal pattern of your period. That's why young girls going through puberty and women approaching menopause commonly have irregular periods. Other common causes of irregular periods include:
A less common cause is severe scarring (adhesions) of the lining of the uterus, a condition that doctors call Asherman syndrome.
- Having an intrauterine device
- Changing birth control pills or using certain medications
- Too much exercise
- Polycystic ovary syndrome
- Pregnancy or breastfeeding
- Stress
- Overactive thyroid (hyperthyroidism) or underactive thyroid (hypothyroidism)
- Thickening of or polyps on the uterine lining
- Uterine fibroids