Why Is My Period So Random?

Medically Reviewed by Minesh Khatri, MD on May 14, 2023
3 min read

Every woman is different -- including their periods. Some happen like clockwork. Others are hit-or-miss and unpredictable. On average, a woman gets their period every 24 to 38 days. A period usually lasts about 2 to 8 days. Is your period irregular -- and if so, does it need treatment?

You may have irregular periods if:

  • The time between each period starts to change
  • You lose more or less blood during a period than usual
  • The number of days that your period lasts varies a lot

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.

You probably don’t need treatment for irregular periods unless they bother you or if you need treatment for another condition that’s affecting your menstrual cycle.

Polycystic ovary syndrome (PCOS) and hypothyroidism are two common causes of irregular periods in women. In general, the goal of treatment is to restore the balance of hormones in the body.

If you have PCOS, your doctor may recommend birth control pills or other hormones to trigger a period. If you have hypothyroidism (underactive thyroid), you may need to take thyroid hormones.

Other things that may help include:

Changing birth control. If you have irregular periods after 3 months of hormonal birth control, your doctor may recommend another type of birth control. Some women develop irregular periods when using Nexplanon, Depo-Provera, or an IUD.

Lifestyle changes. Some women have changes in their period because they exercise too much. You may need to make your workouts less intense or exercise less often. If stress is the problem, learning how to manage your stress -- and possibly also talking with a counselor -- may be helpful.

Extreme changes in your weight can affect your periods. Weight gain can make it harder for your body to ovulate, so weight loss could help with that. But extreme, sudden weight loss can also lead to infrequent or irregular periods.

Hormone therapy (HT). An irregular menstrual cycle is often due to a lack of or imbalance in certain hormones in the body. Doctors often prescribe birth control pills (oral contraceptives) containing the hormones estrogen and progesterone to help control irregular periods. A hormone medication called progestin can also help trigger periods in women who don’t get them.

If you have irregular periods and are trying to get pregnant, your doctor may prescribe other hormone treatments.

Surgery. Sometimes, scarring or structural problems in the uterus (womb) or fallopian tubes may lead to irregular periods. Your doctor may recommend surgery to correct any structural problems or birth defects, particularly if you know you want to have children. It may also be done to remove severe scar tissue in the reproductive tract.

Call your doctor if you have had regular, monthly periods and the pattern changes. Your doctor may give you a physical exam and other tests to rule out pregnancy or a health problem.

Call your doctor if you have any of the following symptoms:

  • You miss three or more periods a year.
  • You get your period more often than every 21 days.
  • You get your period less often than every 35 days.
  • You are bleeding more heavily than usual during your period.
  • You bleed for more than 7 days.
  • You have more pain than usual during a period.