Growth follow-up in 100 children with congenital hypothyroidism before and during treatment.

In order to assess the influence of age at onset of treatment on subsequent growth, height, weight, head circumference (HC) and bone age as estimated by Greulich-Pyle and TW2-RUS methods, 100 children with congenital hypothyroidism (CH) were studied before and during adequate treatment up to 5 years of age. The patients were divided into five groups according to age at the start of treatment: Group 1: < 2 months (n = 26); Group 2: 2-3 months (n = 13); Group 3: 3-6 months (n = 21); Group 4: 6-12 months (n = 20); Group 5: 12-24 months (n = 20). Before treatment, groups 1 and 2 differed significantly from the others in height (p < 0.001). With hormone therapy, catch-up growth was observed in groups 3 to 5, but at age 5 years no differences were found between groups. In all groups, height at 5 years of age correlated significantly with children's midparental height (p < 0.002). Bone age was initially retarded in groups 3 to 5, but approximated the chronological age by age 5 years. Initially, HC was less affected than height and remained relatively larger up to age 5 years in all groups. These findings show that thyroid hormone replacement in CH as late as 24 months corrects the short stature and delayed bone age by age 5 years.