[Screening for congenital hypothyroidism in neonates of Zhejiang Province during 1999-2004].

Objective: To analyze the data of screening for congenital hypothyroidism (CH) newborns in Zhejiang Province during 1999-2004.

Methods: The dried blood samples were collected on filter paper. The levels of thyroid-stimulating hormone (TSH) were measured by time-resolved fluoroimmunoassay, and the serum levels of TSH, triiodothyronine (T(3)) and thyroxine (T(4)) were detected by chemiluminescence. Infants with CH confirmed by neonatal screening were treated with levothyroxine (L-T(4)) initiated with 4-6 g/kg x d(-1 )for 2-3 years. Growth, development and intelligence status, scintigraphy or ultrasonography of thyroid, and bone age were investigated to evaluate the efficacy of therapy during follow-ups.

Result: A total of 1112784 neonates were screened for CH during 1999-2004 with a coverage rate of 63.5%. Of the 6750 suspected CH cases, 6335 (93.8%) were recalled. 764 cases of CH were confirmed with an average incidence rate of 1 case CH per 1457 newborns (1/1457). 244 of 764 patients were followed-up for more than 1.5-2 years. All of them received thyroid by scintigraphy or ultrasonography. Among them 189 cases were found with normal gland, 35 with hypogenetic gland, 11 with ectopic gland, and the remaining 9 didn't show any image of thyroid. The average score of development quotient (DQ) was 106. 9. Among them, the DQ score was less than 85 in 2 cases, less than 90 in 9 cases, less than 100 in 28 cases, and in 68 cases the DQ was greater than 100. The bone age of 122 CH infants was evaluated with the X-ray radiography. In 90 cases of them,the bone age was normal, and 32 cases had progressed from development delay to normal. The height and weigh measured in all 106 cases had reached the related age criteria. The evaluation indicated that 55 cases were found with primary CH, 169 with temporary CH and 20 with subclinical CH.

Conclusion: Neonatal screening for CH and regular treatment for CH patients are important for attaining normal body development and intelligence development of patients.