The Children's Hospital at Westmead, Westmead, NSW, Australia.
J Inherit Metab Dis. 2011 Jun;34(3):827-33. doi: 10.1007/s10545-011-9286-8. Epub 2011 Feb 19.
Very-low-birth-weight babies (VLBW) with hypothyroidism may show a delayed postnatal rise in thyroid stimulating hormone (TSH), mainly due to immaturity of the hypothalamic-pituitary-thyroid axis. Transient hypothyroidism is prevalent in VLBW babies and some affected babies are considered to need treatment. There is disagreement about whether a second screening test is needed in VLBW babies to detect all cases that need treatment.
We included in the study all babies with a birth weight ≤ 1,500 g born in New South Wales and the Australian Capital Territory between January 2006 and December 2008. Newborn screening samples for TSH measurement were taken in the first days of life and again at 1 month. During week 1, a blood-spot TSH level of ≥20 mIU/L was considered positive, and at 1 month a positive level was ≥7 mIU/L, and triggered full investigation.
In the cohort of 301,000 babies, 2,313 VLBW babies survived for testing, and 2,117 repeat screening samples were received. Forty-three babies had transient hypothyroidism, with thyroid function normalising before 2 months of age, usually without treatment. Eighteen babies required treatment beyond 2 months of age (1:128 of surviving babies), 16 having had normal TSH results on initial testing, and 12 having levels below 6 mIU/L.
Significant hypothyroidism, transient or permanent, but persisting beyond 2 months of age is common in VLBW babies. There is a delayed rise in TSH in some, and secondary screening at 1 month of age detects babies deemed by local paediatric endocrinologists as needing treatment.
患有甲状腺功能减退症的极低出生体重儿（VLBW）可能会出现甲状腺刺激素（TSH）的产后延迟升高，主要是由于下丘脑-垂体-甲状腺轴不成熟所致。VLBW 婴儿中普遍存在短暂性甲状腺功能减退症，一些受影响的婴儿被认为需要治疗。对于 VLBW 婴儿，是否需要进行第二次筛查测试以检测所有需要治疗的病例存在争议。
我们将所有出生体重≤1500g 的婴儿纳入研究，这些婴儿于 2006 年 1 月至 2008 年 12 月在新南威尔士州和澳大利亚首都直辖区出生。在生命的头几天和 1 个月时采集 TSH 测量的新生儿筛查样本。在第 1 周，血斑 TSH 水平≥20mIU/L 被认为是阳性，而在 1 个月时，阳性水平≥7mIU/L 并触发全面调查。
在 301000 名婴儿的队列中，有 2313 名 VLBW 婴儿存活接受检测，有 2117 份重复筛查样本。43 名婴儿患有短暂性甲状腺功能减退症，甲状腺功能在 2 个月龄前正常，通常无需治疗。18 名婴儿在 2 个月龄后需要治疗（存活婴儿中 1:128），16 名婴儿在初次检测时 TSH 结果正常，12 名婴儿的水平低于 6mIU/L。
在 VLBW 婴儿中，即使是短暂或永久性但持续至 2 个月龄以后的严重甲状腺功能减退症很常见。在某些婴儿中，TSH 水平会延迟升高，而 1 个月龄时的二次筛查可以检测出当地儿科内分泌学家认为需要治疗的婴儿。
