Department of Neonatal Medicine, Maternal and Perinatal Center, Tokyo Women's Medical University, Tokyo, Japan.
Clin Endocrinol (Oxf). 2018 Oct;89(4):431-436. doi: 10.1111/cen.13793. Epub 2018 Jul 16.
Delayed thyrotropin (TSH) elevation (dTSHe) is common in low birthweight infants. We aimed to clarify the risk factors for the development of dTSHe in infants weighing <2000 g at birth.
According to Japanese guidelines, infants with birthweight <2000 g underwent second capillary TSH screening within 30 days, either at 1 month of age; or when weight reached 2.5 kg; or at discharge. dTSHe was defined as TSH >20 mIU/L by venous sampling following a normal result (<15 mIU/L) at first screening aged 4-6 days. For each infant who developed dTHSe three babies without dTSHe were selected and matched for gestational age and birth year. Small for gestational age (SGA) was defined as a birthweight <10th percentile for the gestational age and sex. A multivariate analysis was performed to identify risk factors for the development of dTSHe.
Among the 911 study infants, 17 infants (1.9%) had dTSHe. The median (range) birthweight in the dTSHe group (796 [388-1912] g) was significantly smaller than the comparison group (961 [408-1981] g) (P = 0.04). The number (%) of SGA infants was significantly higher in the dTSHe group (12 [71%]) than in the comparison group (13 [25%]) (P = 0.001). The multivariate analysis revealed that SGA was an independent risk factor for the development of dTSHe (adjusted odds ratio, 9.0; 95% confidence interval, 2.5-32.8; P = 0.001).
Small for gestational age is an independent risk factor for the development of dTSHe in infants with a birthweight <2000 g. The influence of prematurity, a matching criterion for this study, on dTSHe requires additional study.
延迟的促甲状腺激素（TSH）升高（dTSHe）在低出生体重儿中很常见。我们旨在阐明出生体重<2000g 的婴儿发生 dTSHe 的危险因素。
根据日本指南，出生体重<2000g 的婴儿在出生后 30 天内进行第二次毛细血管 TSH 筛查，时间为 1 个月龄；或体重达到 2.5kg 时；或出院时。dTSHe 定义为静脉采血后 TSH>20mIU/L，首次筛查时结果正常（<15mIU/L），时间为 4-6 天。对于每例出现 dTHSe 的婴儿，选择 3 例无 dTSHe 的婴儿，并根据胎龄和出生年份进行匹配。小于胎龄儿（SGA）定义为胎龄和性别对应的出生体重<第 10 百分位数。采用多变量分析确定 dTSHe 发生的危险因素。
在 911 例研究婴儿中，17 例（1.9%）出现 dTSHe。dTSHe 组（796[388-1912]g）的中位数（范围）出生体重明显小于对照组（961[408-1981]g）（P=0.04）。dTSHe 组（12[71%]）中 SGA 婴儿的数量（%）明显高于对照组（13[25%]）（P=0.001）。多变量分析显示，SGA 是 dTSHe 发生的独立危险因素（调整优势比，9.0；95%置信区间，2.5-32.8；P=0.001）。
对于出生体重<2000g 的婴儿，SGA 是 dTSHe 发生的独立危险因素。该研究的匹配标准早产儿对 dTSHe 的影响需要进一步研究。
