Neonatal and Intensive Care Department, Institute of Mother and Child, Warsaw, Poland.
Neonatal and Intensive Care Department, Medical University of Warsaw, Warsaw, Poland.
Front Endocrinol (Lausanne). 2022 May 10;13:860716. doi: 10.3389/fendo.2022.860716. eCollection 2022.
Thyroid disorders are commonly concomitant with premature birth; however, indications to start therapy remain unclear due to a lack of gestational age (GA)-specific reference ranges. We aimed to evaluate the age-specific thyroid-stimulating hormone (TSH), free thyroxine (FT4) levels and the correlation between TSH and FT4 serum levels and ultrasound thyroid volume in preterm infants.
This was an observational, prospective, single-center study of 98 preterm infants born before 33 weeks GA. The infants were divided into the 24-28 weeks and 29-32 weeks GA groups. TSH and FT4 serum levels were measured at two time points: at postnatal age (PNA) 2 weeks and at postmenstrual age (PMA) 32 weeks; the results were compared between groups at two consecutive time points.
There was a statistically significant between-group difference in FT4 concentration. There was a positive correlation between FT4 and GA at both screening times. FT4 in the 24-28 weeks GA group was significantly lower than in the 29-32 weeks GA group. The mean (standard deviation [SD]) FT4 at PNA 2 weeks was 11.72 ± 2.16 pmol/l for the 24-28 weeks GA group vs. 13.33 ± 1.80 pmol/l for the 29-32 weeks GA group (p<0.001). The mean (SD) FT4 at PMA 32 weeks was 11.96 ± 1.98 pmo/l for the 24-28 weeks GA group vs. 13.33 ± 1.80 pmol/l for the 29-32 weeks GA group (p=0.001). Our results reflect a slow and gradual upward trend of FT4 in the 24-28 weeks GA. It is of interest that the correlation between thyroid volume and FT4 was statistically significant (rho=0.25, p=0.019) for all studied preterm infants. The correlation between thyroid volume and weight was statistically significant for the entire study group (rho=0.37, p<0.001). We did not find statistically significant differences in TSH and FT4 values between consecutive time points at 24-28 weeks GA. The thyroid volume was not significantly different between both groups. The total thyroid volume was 0.26 vs. 0.27 ml for the 24-28 and 29-32 weeks GA groups, respectively.
The results of this study indicate that preterm infants require lower FT4 values depending on GA. Moreover, ultrasound thyroid imaging may facilitate the evaluation of questionable thyroid disorders.
甲状腺疾病常与早产同时发生；然而，由于缺乏特定于胎龄（GA）的参考范围，开始治疗的指征仍不清楚。我们旨在评估早产儿的特定年龄促甲状腺激素（TSH）、游离甲状腺素（FT4）水平以及 TSH 和 FT4 血清水平与甲状腺超声体积之间的相关性。
这是一项针对 98 名胎龄小于 33 周的早产儿的前瞻性、单中心观察研究。将婴儿分为 24-28 周和 29-32 周 GA 组。在两个时间点测量 TSH 和 FT4 血清水平：生后年龄（PNA）2 周和月经后年龄（PMA）32 周；在两个连续时间点比较组间差异。
FT4 浓度在组间存在统计学显著差异。在两次筛查时，FT4 与 GA 均呈正相关。24-28 周 GA 组的 FT4 明显低于 29-32 周 GA 组。24-28 周 GA 组 PNA 2 周时的平均（标准偏差[SD]）FT4 为 11.72±2.16 pmol/L，而 29-32 周 GA 组为 13.33±1.80 pmol/L（p<0.001）。24-28 周 GA 组 PMA 32 周时的平均（SD）FT4 为 11.96±1.98 pmo/l，而 29-32 周 GA 组为 13.33±1.80 pmol/l（p=0.001）。我们的结果反映了 24-28 周 GA 组 FT4 的缓慢而逐渐上升趋势。有趣的是，甲状腺体积与 FT4 之间的相关性在所有研究的早产儿中均具有统计学意义（rho=0.25，p=0.019）。甲状腺体积与体重之间的相关性在整个研究组中具有统计学意义（rho=0.37，p<0.001）。我们未发现 24-28 周 GA 时连续时间点之间 TSH 和 FT4 值存在统计学差异。两组间甲状腺体积无显著差异。两组的总甲状腺体积分别为 0.26 和 0.27 ml。
本研究结果表明，早产儿需要根据 GA 降低 FT4 值。此外，甲状腺超声成像可能有助于评估可疑的甲状腺疾病。
