What stage during puberty will menstruation begin?

Menstruation begins during the pubertal stage of development, which typically occurs between the ages of 12 and 14 in girls. Puberty is a complex process involving physical, emotional, and hormonal changes that mark the transition from childhood to adulthood.

During puberty, the hypothalamus and pituitary gland in the brain release hormones that stimulate the ovaries to produce estrogen and progesterone, the primary female sex hormones. These hormones trigger various changes in the body, including the development of secondary sexual characteristics, such as breast growth, widening of the hips, and the appearance of pubic and underarm hair.

Estrogen and progesterone also play a crucial role in the menstrual cycle. The menstrual cycle is a monthly process involving the preparation of the uterus for potential pregnancy. If pregnancy does not occur, the lining of the uterus (the endometrium) sheds, and menstruation begins.

Menstruation is the process of shedding the endometrial lining through the vagina. It usually lasts for three to seven days and is accompanied by bleeding, cramps, and other symptoms, which can vary in intensity from person to person.

The onset of menstruation marks the beginning of the reproductive phase in a woman's life. However, it is important to note that regular menstruation does not necessarily indicate fertility, and ovulation may not occur immediately after the first period. The menstrual cycle typically becomes regular and ovulatory after a few months or even years in some individuals.