The term menarche contains the Latin word for “month” (men) and the Greek word for “beginning” (arche). Today it’s a term used to describe the first menstrual cycle. The average age for menarche is from 11 to 14, although it can normally occur as early as 9 or as late as 15.

Menarche typically occurs a few years after the beginning of puberty, during which hormones prepare the body for reproduction. The pituitary gland starts to release two hormones—follicle-stimulating hormone and luteinizing hormone—which stimulate growth and the production of estrogen in the ovaries. Over 2 weeks, these levels climb until an egg is released from a follicle in one of the ovaries to travel down the neighboring fallopian tube. At this point, the hormone progesterone is added to the hormones made by the ovaries, causing the uterine lining to mature in preparation for a fertilized egg. But if the egg doesn’t come into successful contact with sperm, the uterine lining is shed during menstruation.

The 28-day reproductive cycle takes a few tries before the body adjusts; most girls don’t ovulate for the first year after menarche. During that time, the cycle is usually not regular; it can range anywhere from 21 to 40 days. Women have menstrual cycles once a month until menopause, which usually begins between ages 45 and 55.

In many societies and cultures around the globe, menarche has been heralded as a sacred rite of passage from girl to woman. The Kolosh Indians of Alaska, for instance, confined pubescent girls in a small hut for a year, while some Cambodian girls had to remain in bed under a mosquito curtain for 100 days. After these periods of confinement, the girls would emerge as marriageable women.

ADDITIONAL FACTS

  1. The earliest known menarche was supposedly at 8 months. The Peruvian girl, Lina Medina went on to give birth to a son when she was an estimated 6 to 8 years old.
  2. Only the superficial part of the uterine lining is shed during menstruation. The basal layer remains and grows into a thick new lining in every normal cycle.