Final answer:
The medical term for the first menstrual period is menarche, which signifies the commencement of menstruation in pubertal females as the endometrium is shed through the vagina.
Step-by-step explanation:
The Medical Term for First Menstrual Period
The medical term for the first menstrual period is menarche. Menarche marks the onset of menstruation in a pubertal female and is a significant milestone in female reproductive development. It is characterized by the shedding of the inner portion of the endometrium out through the vagina—also referred to as menstruation or menstrual period. The menstrual cycle includes several phases, with menstruation being the first phase. This process signifies that the female's reproductive system has reached a level of maturity capable of fertility.
Menarche typically occurs around the average age of 12.4 years, however, it can occur anytime between the ages of eight and 16 and still be considered normal. To further understand menstruation, it is also necessary to know about menopause, which occurs around the age of 50, marking the conclusion of menstrual periods. Moreover, the menses phase is the phase of the menstrual cycle in which the endometrium is shed if fertilization of an egg has not taken place.