Definition
Menstruation, or a menstrual period, refers to the monthly process in which the uterus sheds blood and tissue because pregnancy did not occur.
Not having or missing a menstrual period is called amenorrhea. The types are:
- Primary—Menstruation has not begun in an adolescent around 16 years of age. Most females begin menstruating between 9-18 years of age, though the average is 12 years of age.
- Secondary—A woman who has previously menstruated misses 3 or more periods in a row.

Causes
The most common cause of secondary amenorrhea is pregnancy. In non-pregnant women, it may be due to a variety of factors.
Risk Factors
Factors that may increase the risk of amenorrhea include:
- Dramatic weight loss (which can occur from extreme diets, eating disorders, or excessive exercise) or dramatic weight gain
- Malnutrition
- Birth defects, including lack of female reproductive organs
- Chromosomal or hormonal abnormalities
- Certain conditions, such as a thyroid disorder or pituitary tumor
- Medications, such as certain contraceptives
- Emotional distress
- Uterine scarring
Symptoms
The main symptom for primary amenorrhea is the absence of a menstrual period in a female by age 16 years or older. The main symptom for secondary amenorrhea is 3 or more missed periods in a row in a woman who has previously had menstrual periods.
When Should I Call My Doctor?
Call your doctor if you:
- Have not had your first period and are aged 16 years or older
- Miss having your period
Diagnosis
You will be asked about your symptoms and medical history. A physical exam will be done.
Your bodily fluids may be tested. This can be done with:
- Blood tests
- Urine tests
Images may be taken of your bodily structures. This can be done with:
Treatment
Treatment will depend on what is causing amennorrhea. Examples include:
- Weight-related cause—A healthy caloric intake and exercise routine usually restores hormonal balance and menstruation.
- Birth defect—Surgery may be needed.
- Hormonal irregularity—Hormonal therapy may be needed.
- Emotional distress—Relaxation techniques, therapy, and exercise may help to decrease stress.
- Pituitary tumor—Surgery, radiation therapy, or medication may be needed.
Prevention
Amenorrhea may or may not be preventable, depending on the cause. Follow these general guidelines to prevent amenorrhea:
- Maintain an appropriate level of body fat.
- Get help for an eating disorder.
- Treat conditions that can lead to amenorrhea, such as polycystic ovary syndrome, pituitary tumor, and hypothyroidism.
Revision Information
- Reviewer: EBSCO Medical Review Board Beverly Siegal, MD, FACOG
- Review Date: 09/2017 -
- Update Date: 08/08/2014 -