Weight and growth requirements for menarche in teenage girls with eating disorders, weight loss and primary amenorrhea.

To investigate weight and growth requirements for menarche in girls with eating disorders (ED), weight loss and primary amenorrhea. Growth charts from school health services and measurements of weight and stature throughout treatment were obtained for 47 such girls. Weight loss started at an age of 12.4 +/- 1.6 years from a top weight of 41.7 +/- 7.1 kg. Approximately a year later they had lost 5.1 +/- 4.3 kg and grown only 2.8 +/- 3.5 cm. Following treatment and weight gain, growth accelerated and the girls reached a peak growth velocity of 4.3 +/- 2.6 cm/year 2 years before menarche which occurred at an age of 15.5 +/- 1.6 years at a weight of 52.2 +/- 5.3 kg. Menarche occurred within a wide range of weights but could be predicted by a linear regression on prepubertal weight (R(2) = 0.39; p < 0.001). Following treatment, girls with ED and primary amenorrhea progress through puberty at a slowed rate. The weight required for menarche can be predicted by the prepubertal weight which may represent the individual's normal growth track unaffected by the ED. (c) 2008 S. Karger AG, Basel