Does every girl menstruate? If not, what will happen?
The absence of menstruation is called amenorrhea. Primary amenorrhea refers to the absence of menstruation in someone who has not had a period by age 15, and the most common causes relate to hormone levels. Secondary amenorrhea refers to the absence of three or more periods in a row by someone who has had periods in the past, and the most common cause is pregnancy. Causes of amenorrhea may be normal (e.g., pregnancy or menopause), medication side effects, or medical problems. Amenorrhea can cause infertility, problems related to pregnancy, psychological stress, osteoporosis, cardiovascular disease, and pelvic pain. This is due to hormonal imbalance or anatomical problems.