Why do girls have menstrual periods?

Menstrual periods are a natural part of a woman's reproductive cycle. They occur when the lining of the uterus (the endometrium) is shed and expelled from the body through the vagina. This process is triggered by a drop in the levels of the hormones estrogen and progesterone, which are produced by the ovaries.

Menstrual periods typically begin between the ages of 12 and 15, but can start as early as age 9 or as late as age 18. The average menstrual cycle lasts about 28 days, but can range from 21 to 35 days. Menstrual periods usually last for about 3 to 7 days, but can be shorter or longer.

The symptoms of menstrual periods can vary from woman to woman. Some common symptoms include:

* Cramps in the lower abdomen

* Back pain

* Bloating

* Headaches

* Mood swings

* Fatigue

* Breast tenderness

* Acne

Menstrual periods are a normal part of life for women. However, if you have any concerns about your menstrual cycle, you should talk to your doctor.