The menstrual cycle is the series of changes a woman's body
goes through to prepare for a possible pregnancy. Most girls start having
periods between the ages of 11 and 15.
A girl who has not had her
first period by age 15 has what is called primary amenorrhea. This is different
from infrequent or light menstrual cycles, which are very common in teen girls, particularly in the first couple of years after menstruation begins.
Primary amenorrhea is also different than if a girl starts having periods, but
then stops having periods for at least 3 cycles.
Causes of primary
Problems with the structure of the vagina, such
as skin covering the opening of the vagina (imperforate
Absence of or an abnormal pelvic organ, such as the uterus
Medicines or medical treatment in childhood that
may have damaged the ovaries, such as chemotherapy or radiation treatment for
cancer. Chemotherapy or radiation treatment in women may cause irregular
If no problem can be found to explain why you are not having
periods, your doctor may prescribe birth control pills to help control your
cycle. These will also help keep your bones strong, reducing your risk for
brittle bones (osteoporosis). Your doctor also may prescribe calcium
supplements to help ensure that your bones stay healthy.
have not begun to develop breasts or pubic hair by age 14 may have an increased
chance of having amenorrhea.
You can still become pregnant even
though you are not menstruating. Practice birth control if you do not wish to
How this information was developed to help you make better health decisions.