Amenorrhea is the abnormal absence of menstrual periods. Generally speaking, there are three categories of people who have experienced amenorrhea:
People with a uterus who have never had a menstrual period by age sixteen.
People with a uterus who have not had a period for two to three months or more.
People with a uterus who have irregular periods that may vary from 35 to 90 days.
Determining why a person with a uterus over 16 years of age has never had a menstrual period is essential for proper treatment; identifying a reason may involve several blood hormone tests, and possibly referral to an endocrinologist.
Missing periods after regular periods have begun is much more common, especially among college students. Changes in environment, diet, stress, as well as medical problems can cause variability in menstrual cycles.
If you menstruate fewer than four times per year or if you miss three consecutive periods, you need to see a health care provider. If you are sexually active, you should see a provider for a pregnancy test after one missed or late period. You should also see a provider if you notice breast/nipple discharge, or if you notice unusual facial hair or other body hair growth.