It is, however, a costly examination and perhaps not as precise as breast size. As in boys, pituitary gonadotropin secretion increases, and the ovary develops. Plasma estradiol is markedly increased between the ages of 10 and 12 years. However, there are huge variations in plasma estradiol levels during a 24-h period, even after menarche. Therefore the measurement of plasma estradiol is not a reliable marker of the onset of puberty.
Nutrition is a factor for the onset of puberty and menarche.
Although the concept still remains absolutely valid there is a considerable variation within that critical weight. It depends on the adolescent height and should be adjusted for height. The peak height velocity was reduced to 9.5 cm. In advanced puberty a higher peak height velocity than in normal puberty is observed. During puberty there is a marked increase in bone mass and particularly in bone mineral density.