Division of Neonatology, Department of Pediatrics, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
Department of Pediatrics, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
Turk J Pediatr. 2023;65(4):562-571. doi: 10.24953/turkjped.2023.94.
Transient hypothyroxinemia of prematurity (THOP) is characterized by low thyroxine (T4) levels with normal thyroid-stimulating hormone (TSH) levels. This study aimed to determine the incidence and factors associated with THOP.
This prospective cohort study included neonates who were born before 37 weeks of gestation in the neonatal intensive care unit (NICU) between April 2017 and December 2020. Serum TSH and free thyroxine (FT4) levels were routinely screened at 3-5 days and 2, 4, and 6-8 weeks postnatally. The criteria for diagnosis of THOP were a TSH level < 7 mU/L with a FT4 level < 0.8 ng/dL at any screening timepoint.
The incidence of THOP in infants born before 28, 34, and 37 weeks of gestation was 39.5 (17/43), 8.4% (29/343), and 4.8% (35/722), respectively. A multivariate analysis revealed that a gestational age of < 28 weeks (adjusted odds ratio [aOR]: 5.35, 95% confidence interval [CI]: 1.89-15.13, p=0.002); 5-min Apgar score of ≤3 (aOR: 5.72, 95% CI: 2.2-14.89, p < 0.001); and treatment with aminophylline (aOR: 2.95, 95% CI: 1.08-8.11, p=0.037), dobutamine (aOR: 4.12, 95% CI: 1.55-10.98, p=0.004), or morphine (aOR: 4.91, 95% CI: 1.29-18.74, p=0.011) were associated with an increased risk of THOP. The TSH and FT4 levels in infants with THOP returned to normal ranges by 2 weeks of age.
THOP is frequently found in preterm infants. An extremely low gestational age, a low Apgar score, and the use of certain medications in the NICU are risk factors for the development of THOP. Therefore, a thyroid screening program should be implemented for evaluating congenital hypothyroidism (CH) and THOP in preterm neonates in all settings.
早产儿一过性甲状腺功能减退症（THOP）的特征是甲状腺刺激激素（TSH）水平正常而甲状腺素（T4）水平降低。本研究旨在确定 THOP 的发生率和相关因素。
本前瞻性队列研究纳入了 2017 年 4 月至 2020 年 12 月在新生儿重症监护病房（NICU）中出生胎龄<37 周的新生儿。在出生后 3-5 天、2 周、4 周和 6-8 周时，常规筛查血清 TSH 和游离甲状腺素（FT4）水平。THOP 的诊断标准为任何筛查时间点 TSH 水平<7 mU/L 且 FT4 水平<0.8 ng/dL。
胎龄<28 周、34 周和 37 周的新生儿 THOP 发生率分别为 39.5%（17/43）、8.4%（29/343）和 4.8%（35/722）。多变量分析显示，胎龄<28 周（调整优势比[aOR]：5.35，95%置信区间[CI]：1.89-15.13，p=0.002）；5 分钟 Apgar 评分≤3（aOR：5.72，95% CI：2.2-14.89，p<0.001）；以及在 NICU 中接受氨茶碱（aOR：2.95，95% CI：1.08-8.11，p=0.037）、多巴酚丁胺（aOR：4.12，95% CI：1.55-10.98，p=0.004）或吗啡（aOR：4.91，95% CI：1.29-18.74，p=0.011）治疗与 THOP 风险增加相关。THOP 患儿的 TSH 和 FT4 水平在 2 周龄时恢复正常范围。
THOP 常见于早产儿。极低的胎龄、较低的 Apgar 评分以及 NICU 中使用某些药物是发生 THOP 的危险因素。因此，应在所有环境中为早产儿实施甲状腺筛查计划，以评估先天性甲状腺功能减退症（CH）和 THOP。
