Objective: To study the risk factors and treatment outcome of hypothyroidism in very low birth weight/extremely low birth weight (VLBW/ELBW) infants.
Methods: The VLBW/ELBW infants who were diagnosed with hypothyroidism from September 2018 to December 2019 were enrolled as the case group (n=29). The children with normal thyroid function, matched at a ratio of 1 : 3, were enrolled as the control group (n=87). Clinical features were compared between the two groups. The correlation of thyroid function with gestational age and birth weight and the risk factors for hypothyroidism were analyzed.
Results: A total of 162 VLBW/ELBW infants who met the inclusion criteria were enrolled, with 29 infants in the case group (an incidence rate of hypothyroidism of 17.9%). The lower the birth weight, the higher the incidence rate of hypothyroidism (P<0.05). Triiodothyronine (T3) and free T3 were positively correlated with gestational age (P<0.05). T3 and free thyroxine were positively correlated with birth weight (P<0.05). Small for gestational age, multiple birth, maternal age ≥ 35 years, and use of dopamine were independent risk factors for hypothyroidism (P<0.05). In the case group, 16 infants were treated with levothyroxine (5-10 μg/kg daily), and the thyroid function returned to normal after 2 weeks of treatment.
Conclusions: There is a high incidence rate of hypothyroidism in VLBW/ELBW infants. Small for gestational age, multiple birth, advanced maternal age, and use of dopamine are risk factors for hypothyroidism. The infants treated with levothyroxine should be followed up regularly to ensure an appropriate dose.
目的: 分析极低/超低出生体重（VLBW/ELBW）患儿甲状腺功能减退的危险因素和治疗情况。
方法: 选择2018年9月至2019年12月诊断为甲状腺功能减退的VLBW/ELBW患儿为病例组（n=29），按照1：3比例匹配甲状腺功能正常的VLBW/ELBW患儿作为对照组（n=87），比较两组患儿的临床特征，分析甲状腺功能与出生胎龄、出生体重的相关性及甲状腺功能减退的危险因素。
结果: 符合纳入标准的VLBW/ELBW患儿共162例，其中病例组29例，甲状腺功能减退发生率为17.9%。出生体重越低，甲状腺功能减退发生率越高（P < 0.05）；三碘甲状腺原氨酸（T3）、游离三碘甲状腺原氨酸（FT3）与出生胎龄呈正相关（P < 0.05），T3、游离甲状腺素（FT4）与出生体重呈正相关（P < 0.05）。小于胎龄儿、多胎、孕母≥35岁、使用多巴胺是发生甲状腺功能减退的独立危险因素（P < 0.05）。病例组中16例患儿给予左旋甲状腺素（每日5~10 μg/kg）治疗，甲状腺功能在治疗2周后恢复正常。
结论: VLBW/ELBW患儿甲状腺功能减退的发生率较高，小于胎龄儿、多胎、孕母高龄、应用多巴胺是其发生甲状腺功能减退的危险因素，应用左旋甲状腺素治疗的患儿需定期随访，以保证用药剂量适宜。