Estrogen treatment in tall girls

36 tall girls aged 10.3 to 15.5 years were treated with ethinylestradiol (0.5 mg/day) and norethisterone (15 mg/day). To date treatment for seventeen girls has been completed. Before treatment their bone age ranged from 11.0 to 13.5 years and mean height prediction was 185.19 cm (181.40-193.00 cm). After about two years of treatment their final height averaged 178.96 cm (171.60-183.50 cm). Predicted height was reduced by an average of 6.23 cm. The reduction in final height was significantly greater when therapy was started before a bone age of 12 years. Thirteen girls, re-examined after discontinuation of therapy, all had regular menstrual bleeding within six months. There were no serious or irreversible side effects during the period of observation.