What's wrong with girls not having their periods?

There are many factors that girls do not come to menstruation. They are divided into primary amenorrhea and secondary amenorrhea. Primary amenorrhea is mostly congenital without uterus and vagina, and cannot produce menstruation. Secondary amenorrhea may be due to long hours of work pressure, mental stress will cause menstrual delay or endocrine disorders, followed by diet and mood will also change the menstrual cycle. Taking contraceptives or intrauterine contraceptive rings after coitus may cause menstrual delay. In addition, consider whether there is sex life, if there is sex life to consider whether pregnant, will also show menstrual stop. Women after the age of 45 may show menstrual stop. Girls do not come to the aunt do not over-nervous, relax, do not over-exercise.