Final answer:
A woman's first menstrual cycle, menarche, typically begins around age 12 or 13 and marks the start of her reproductive years. Menarche can occur within a wide age range, due to genetic and environmental factors, with menstrual cycles varying among women. The end of a woman's reproductive years is signified by menopause, occurring on average around the age of 52.
Step-by-step explanation:
A woman's first menstrual cycle typically occurs around age 12 or 13 years, an event known as menarche. This significant biological change marks the onset of puberty and the start of reproductive capability. While the average age in the United States is 12.4 years, the normal range for menarche can vary widely, from as early as 8 to as late as 16 years. This variation may be attributed to genetic, environmental, and dietary factors.
Menstruation is just the beginning phase of the menstrual cycle, which averages 28 days but can normally range from 21 to 45 days. The duration of menstrual period itself typically lasts about five days, with a normal range of two to seven days. Understanding the menstrual cycle is crucial as it signifies a woman's fertility period, which peaks in the twenties and gradually declines until it ceases at menopause, around the average age of 52.
Menopause, which marks the end of a woman's reproductive years, occurs when the menstrual cycles stop, generally by the early fifties. As with menarche, menopause age can also vary, influenced by numerous biological and environmental factors. It's important to recognize that these reproductive milestones can occur at different ages and be influenced by overall health, including smoking, which can lead to an earlier onset of menopause.