School achievement in children with hypothyroidism detected at birth and search for predictive factors.

Neonatal screening of hypothyroidism started in 1975, and now sufficient hindsight is gained to assess school results in children with hypothyroidism and compare them to IQ tests. From the 85 cases of hypothyroidism detected in the Midi-Pyrénées area, 40 have enrolled in or finished primary school and 18 started secondary school. School achievement was assessed by school test results in French and mathematics using specific grids for each class and by retention rates. These results were compared to control groups. The hypothyroid group obtained identical results in French to those of the control groups but scored lower in mathematics. Grade retention rated higher in hypothyroid children (20%) than in the control groups (12.5%), especially in the first primary school grade. The search for predictive severity factors revealed significant differences between the grade repeater group and the nonrepeater group: more cases of athyrosis (75 vs. 25% for ectopia), lower T4 levels at birth, lower bone surface, lower IQ at 4 and 7 years, neurological troubles of fine motricity and coordination, and lower socioeconomic level. These results should shortly be taken into consideration in order to isolate a group at risk and undertake specialized care to improve school results in this group.