目的:探讨左旋甲状腺素钠治疗新生儿甲状腺功能减低症(CH)的临床效果,研究不同病情程度的最佳初始剂量及初始时间。方法:对新生儿确诊CH的168例患儿作为研究对象,根据患儿首次甲状腺功能化验结果,将其分为先天性CH组、亚临床CH组及高TSH组。应用左旋甲状腺素钠治疗,常规初始剂量5~10μg·kg-1·d-1,观察3组患儿治疗2、4及12周时的甲状腺功能指标及治疗至2岁时患儿的身高、体重和智力情况。结果:初始治疗2周时,108例先天性CH中甲功低下21例,正常78例,继发甲亢9例;43例亚临床CH中甲功低下8例,正常31例,继发甲亢4例;17例高TSH中甲功低下1例,正常12例,继发甲亢4例。治疗12周时,168例患儿的FT4均为正常,但仍有4例患儿TSH高于正常范围。2岁时检测患儿身高、体重及智能的变化情况,30天以内开始治疗的患儿各项指标均高于30天后开始治疗的患儿,差异有统计学意义(P<0.05)。结论:经确诊的CH患儿应尽早进行激素替代治疗,治疗时间越早其预期越好,推荐初始剂量为5~10μg·kg-1·d-1。 Objective: To investigate the clinical effect of levothyroxine in treating neonatal hypothyroidism (CH) and to study the optimal initial dose and initial time of different severity of disease. Methods: A total of 168 newborns diagnosed with CH were enrolled in this study. According to the results of the first thyroid function tests, they were divided into congenital CH group, subclinical CH group and high TSH group. Application of levothyroxine sodium treatment, the initial initial dose of 5 ~ 10μg · kg-1 · d-1, observed 3 groups of children at 2, 4 and 12 weeks of thyroid function indicators and treatment of children up to 2 years of age height, Weight and intelligence. Results: At the initial 2 weeks of treatment, 108 patients with congenital CH were found to have hypothyroidism in 21 cases, normal 78 cases and secondary hyperthyroidism in 9 cases. Among 43 cases of subclinical CH, 8 cases were hypokalemia, 31 cases were normal, followed by hyperthyroidism Cases; 17 cases of high TSH hypothyroidism in 1 case, normal in 12 cases, 4 cases of secondary hyperthyroidism. Treatment of 12 weeks, 168 cases of children with FT4 are normal, but there are still 4 cases of children with TSH higher than the normal range. At 2 years of age, the changes of height, weight and intelligence in children were detected. All the children who started treatment within 30 days were higher than those who started treatment after 30 days. The difference was statistically significant (P <0.05). Conclusion: The diagnosed children with CH should be treated with hormone replacement therapy as soon as possible. The earlier the treatment is, the better the expectation is. The recommended initial dose is 5 ~ 10μg · kg-1 · d-1.