Impact of different doses of ethinyl oestradiol on reduction of final height in constitutionally tall girls

Fifty-two tall girls were treated for constitutionally tall stature with different ethinyl oestradiol (EE) dosages. They were divided into three different treatment groups: group B (100 micrograms EE/day; n = 11); group C (300 micrograms; n = 25) and group D (500 micrograms; n = 16) and compared with an untreated group A (n = 21) matched for age, height, bone age (BA) and height prediction. Using the height prediction method TW II, EE treatment reduced final height compared with the untreated girls in a weak dose-dependent manner, 2.3 cm (100 micrograms/day), 3.0 cm (300 micrograms/day), and 3.8 cm (500 micrograms/day). Such a dose dependency was not found on applying the Bayley-Pineau height prediction method (100 micrograms/day; 4.1 cm; 300 micrograms/day: 4.2 cm; 500 micrograms/day: 4.5 cm). However, there was a striking inverse correlation of the BA at the onset of treatment with the height reduction achieved using the TW II method (r: -0.43; P0.001). Importantly, girls with a BA below 12 years at the onset of treatment experienced a height reduction of more than 6 cm. CONCLUSION The EE dose used in the range of 100-500 micrograms/day is not crucial for the amount of height reduction in tall girls. In general high dose EE treatment should be given restrictively, and especially so in girls with a BA (TW2 RUS-ZH) above 12.0 years.