Menarche

Under menarche ( altgr. μήν MEN, month ' and ἀρχή archê ' beginning ' ) is defined as the first occurrence of menstruation in puberty.

The menarche occurs in the course of pubertal development, but does not signal clearly the reproductive capacity ( ovulatory cycle), since it is usually anovulatory, so running without ovulation hormone withdrawal bleeding during the first menstrual bleeding. A regular ovulation usually occurs after one and a half to two years.

Fluctuations at the time of entry

Menarche is characteristic for the development of a discrete description of puberty particularly suitable, such as the spermarche boys. The timing is dependent on ethnic, geographical, individual and nutritional factors. For girls, the time span between the appearance of the first signs of puberty ( pubic hair and breast development ) and menarche on average from 2.2 to 2.7 years, but can vary between individuals from less than one year and more than six years. In Germany, the menarche occurs at most about girls between 10 and 16 years of age. In the early 19th century was the time two years later. A dramatic shift in the timing of menarche then stepped around 1850 for the first time. Since then, she takes on average each decade three to four months earlier instead. The differences in gestational age between population groups appear primarily as a result of environmental conditions and specific dietary patterns, but also influenced by hygiene and sanitation or medical culture conditions. Thus, for example, showed that in Europe and the U.S., the age at menarche from 11.5 to 14.5 years is.

Cases are assigned in which the menarche has lain before the 6th birthday.

With the same living conditions in the populations and genetic differences explain the scatter. It is argued that the achievement of a certain proportion of body fat for the onset of puberty is significantly ( > 17 % share), so that young professional sportsmen and underweight have a delayed maturation. For statistical surveys, we know that the menarche apparently correlated with the attainment of a body weight of 48 kg.