Menarche

Menarche refers to the first menstrual flow experienced by a girl during puberty. Menstruation means that the physiological and hormonal changes underlying reproductive processes have matured sufficiently to produce the endometrial lining of the uterus, which is sloughed off at the end of the menstrual cycle if implantation of a fertilized ovum has not occurred.

Menarche typically occurs after other pubertal changes are well established, and marks the completion of puberty. The mean age of menarche for girls in the United States is twelve, but it may occur normally from ages ten to sixteen. Early menstrual cycles are often irregular and may include no ovulation or multiple ovulations.

Menarche often is acknowledged by family or community rituals, recognizing the adolescent's entrance into womanhood and sexual potential. Challenges of adolescence for a girl include incorporating the new status and potential into her self-concept and coping with reactions of family and peers.