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Clinical Reference Systems: Pediatric Advisor 10.0

Menstrual Period, Late or Missed

Menstrual cycles vary in length from one woman to the next. They may occur at at the same time each month or be irregular. A menstrual period is considered late if it is 5 or more days overdue according to your usual pattern of periods. A period is considered missed if there is no menstrual flow for 6 or more weeks.

What is the cause?

  1. Pregnancy

    This is the most common cause of missed periods in teenage girls. If you have had sex even once in the past several months, see your doctor for a pregnancy test before you consider any of the other possible causes.

  2. Stress

    Stress is the second most common cause of late or missed periods in teenagers. It may be emotional stress (for example, breakup with a boyfriend or final exams) or depression. Or it may be physical stress to the body, such as a severe illness, a sexually transmitted infection, rapid weight loss or gain, or strenuous exercise. Dieting or binging and purging may interrupt menstrual cycles. Changes in your usual routine (for example, going on vacation) may also cause your period to be late or missed.

  3. Normal development

    During the first couple of years of menstruation many teenagers have irregular periods. During this time the body's hormones are not yet "fine-tuned," so the ovaries may not release an egg once every month. As a result, your cycles may be irregular, occurring as close together as 2 weeks or as far apart as 3 months.

  4. Hormone imbalance

    Hormone imbalance is rarely the cause of missed periods.

    In teenagers, polycystic ovary syndrome is the most common type of hormone imbalance that affects the menstrual cycle. Polycystic ovaries may cause irregular cycles, increased body hair, acne, and weight gain.

    Sometimes when you stop taking birth control pills you may have a temporary hormone imbalance and loss of periods. If you are having sex, be sure to use another reliable method of birth control because you could still become pregnant.

    Problems of the thyroid gland, pituitary gland, adrenal glands, or ovaries can be rare causes of irregular periods.

How do I know what the cause is?

  1. Pregnancy

    A positive pregnancy test is the only way to be certain of pregnancy. It is best to see your doctor for a pregnancy test because home test kits can be confusing and give misleading results. In addition, it's important to have a supportive person available to answer all your questions if you are pregnant. Breast swelling, weight gain, and nausea are additional signs of pregnancy. You may wish to have a parent (or other adult you trust) go with you.

  2. Stress

    Some stress is a normal part of daily life. Only you can know if you are under too much stress. Read the paragraph about stress under "What is the cause?" Consider whether any of these events have happened lately in your life.

  3. Normal development

    If your doctor finds nothing abnormal during your physical exam and you've been having periods for 2 years or less, your irregular periods may be part of your normal development. Remember, if you have had sex, go to your doctor's office for a pregnancy test when your period is late for you, even if you normally have irregular cycles. Also, if you are having sex, read the information on birth control or discuss it with your health care provider.

    See Birth Control Methods

  4. Hormone imbalance

    If you have missed several periods without an explanation, your doctor can check your ovaries and look for any signs of hormone imbalance. Blood tests can be done to measure hormone levels.

When will my period return to normal?

  1. Pregnancy

    It is important to identify pregnancy early so that you can discuss the options available to you and start prenatal care. Early prenatal care helps ensure a healthy baby. Call your doctor if you have any bleeding during your pregnancy. You will not have a normal period until after the baby is born.

  2. Stress

    Your periods should return when the activities or situations that are stressing you are eliminated or changed.

  3. Normal development

    Most girls' menstrual cycles become fairly regular as their hormone levels become mature and synchronized. A few women will continue to have irregular cycles as their normal pattern.

  4. Hormone imbalance

    Most often a hormone imbalance can be treated after your doctor discovers the cause.

How can I take care of myself?

  1. Keep a calendar of when your periods occur and how long they last. This information can help your doctor make a correct diagnosis. Take it to your appointment.

  2. Eat healthy foods and keep your weight steady. If you are overweight, a balanced diet and regular exercise will help you lose weight slowly (no more than 2 pounds a week). If you are underweight, eat more.

  3. If you follow a strenuous exercise program, consider cutting back until your periods come back.

  4. If you have sex, always use birth control. Talk to your doctor about the available methods.

  5. If you think you might be pregnant, get a pregnancy test whenever your period is 5 or more days late. Don't wait. Confidential testing and counseling are available in most doctors' offices and clinics. Take your first morning urine specimen with you for the test. Keep it refrigerated until you take it in.

Call Your Physician During Office Hours If:

  • You think you might be pregnant.
  • You have had sex and your period is at least 5 days late.
  • Your period does not return within 6 weeks.
  • You need help with gaining or losing weight.
  • You need help for binging/purging or excessive dieting.
  • You need help for stress or depression.
  • You have an abnormal vaginal discharge or abdominal pains.
  • You develop excessive facial or body hair, significant acne, trouble with your eyesight, persistent headaches, a deepening of your voice, a coarsening of your skin, hot or cold sensations when no one else feels them, or other symptoms that concern you.
  • Your period does not return within 6 months after stopping birth control pills and you aren't pregnant.
  • You have other questions or concerns.

Written by Kathleen A. Mammel, M.D., Director, Adolescent Pediatrics, William Beaumont Hospital, Royal Oak, Michigan.
Copyright 1999 Clinical Reference Systems