ABSTRACT
Menarche is probably the best indicator a girl has of “growing up.” This developmental milestone signifies the change from child to woman. This significant event is caused by heightened activity of the sex hormones. Studies to determine median age of menarche in a population are easy and inexpensive to carry out. However, in order to obtain reliable results, certain methodologies must be followed. In any population, 95% of the girls will experience menarche anywhere from 2.5 to 3 years before to 2.5 to 3 years after the average age of menarche for the population. Different European countries are actually quite similar in average age of menarche, although Mediterranean populations tend to be somewhat earlier than English, Dutch, or Scandinavians. The average age of menarche has been decreasing in Europe and North America for the last 150 years.
