Absent menstruation, or amenorrhea, is when a young woman has reached the age of 16 and has not yet had her first period. It is also when a woman who previously had regular periods misses three or more cycles in a row.
There are many possible reasons for absent periods. These include natural causes, such as pregnancy, and lifestyle factors, like body weight and exercise levels. In some cases, hormonal imbalances or physical defects of the reproductive organs may be the cause.
It is important to see your doctor because the underlying cause of missed periods may require treatment.
There are two types of absent menstruation. The type depends on whether menstruation has never occurred or has occurred but is then absent.
Primary amenorrhea occurs when a young woman has reached or passed the age of 16 and still has not had her first period. Most girls begin having periods sometime between the ages of 9 and 18, but 12 is the average age. According to the National Institutes of Health (NIH), less than one percent of girls experience this type of absent menstruation (NIH, 2010).
A woman with secondary amenorrhea has begun menstruation, often at a normal age, but has missed her period for at least three cycles (six months). About four percent of women experience secondary amenorrhea that is not caused by pregnancy (NIH, 2010).
There are several causes of both primary and secondary absent menstruation. Some are natural, such as pregnancy. Others are underlying conditions that need to be treated.
When a girl starts her period later than average, it is not necessarily abnormal. However, it is possible that the late start indicates a serious health problem. Disorders of the genes or chromosomes, such as Turner syndrome, Sawyer syndrome, or adrenogenital syndrome, may cause primary amenorrhea. These diseases can cause physical problems with the reproductive organs.
Hormonal issues may also cause late menstruation. Diseases in the hypothalamus or pituitary glands in the brain can cause these. Tumors in the glands or disorders such as polycystic ovary syndrome (PCOS) can also cause a hormonal imbalance.
Physical defects in the reproductive organs may also cause a girl to have primary amenorrhea. These can result from birth defects, tumors, or infections that occurred in the womb or shortly after birth.
Both obesity and the eating disorder anorexia can cause a late start of menstruation. Lifestyle factors, such as excessive exercise, and mental, emotional, and physical stress can cause late periods.
Many of the same factors that cause primary amenorrhea can also cause the secondary condition. Natural causes of missed periods, such as pregnancy, breastfeeding, and menopause, are the most likely reasons for secondary amenorrhea.
Physical and lifestyle factors are common reasons for missed periods. These can include:
- having low body fat
- exercising too much
- having serious anxiety or stress
- losing weight rapidly
Hormonal imbalances can cause a woman to miss periods. This could be from tumors in the pituitary gland or a thyroid problem. It could also be from polycystic ovarian syndrome (PCOS) or premature ovarian failure.
Certain medications can cause secondary amenorrhea. Antipsychotics, such as Phenothiazine, and antidepressants may be to blame. Blood pressure drugs, including reserpine, and some chemotherapy drugs can also cause a problem. Taking birth control pills and then stopping may lead to several months of absent periods before the cycle returns to normal.
In rare cases, missed periods could be a symptom of Asherman syndrome. This occurs when scarring in the uterus after surgery prevents menstruation.
A girl who has not yet started her periods should see a doctor if she is 16 or older. If she is 14 or older and has not experienced any signs of puberty, she should also see a doctor.
It is important to see your doctor if you have missed three or more periods in a row.
When you see your doctor about missed periods, he or she will give you a physical exam. Your doctor will ask you a series of questions about your periods, your cycle, your lifestyle, and any other symptoms you are experiencing. In the case of secondary amenorrhea, your doctor’s first test will likely be for pregnancy. If that is ruled out, you may need more tests to determine the underlying cause.
A blood test will allow your doctor to check hormone levels in your body. Prolactin, luteinizing hormone, and follicle stimulating hormone are all related to menstruation. Determining these levels can help your doctor determine or rule out a cause for your absent periods.
If a hormone imbalance is to blame, your doctor will likely prescribe medication to normalize hormone levels.
If a structural problem with your reproductive organs is suspected, your doctor may perform an ultrasound of your uterus and ovaries. This involves using sound waves to create a picture of the organs. You may also need to have a computed tomography (CT) scan of your head. This will help your doctor see if a tumor in your pituitary gland is the cause.
In cases where a physical abnormality or a tumor is present, surgery may be required.
If your doctor suspects that lifestyle factors are at the root of your absent menstruation, you should be able to correct the condition with simple changes. For example:
- Get moderate exercise.
- Eat a healthy diet.
- Maintain a normal weight for your age and height.
- Lower your stress levels.