Abstract: Isolated maternal hypothyroxinemia（IMH） is a manifestation of thyroid hormone deficiency during pregnancy，which may affect fetal neurodevelopment and increase the risk of miscarriage，preterm birth，and gestational diabetes. However，uncertainties remain regarding its specific mechanisms，optimal treatment plan，and long-term effects. This paper summarizes the differences in thyroid hormone levels between pregnancy and non-pregnancy states. By reviewing relevant literature，we provide a comprehensive analysis of the disease's etiology，its impact on both mother and infant，and treatment strategies. The paper suggests that iodine deficiency and iron deficiency are the primary causes of isolated hypothyroxinemia during pregnancy. However，conclusive evidence regarding the association of factors such as placental growth factor with the disease is still lacking. At present，the negative effects of IMH on perinatal motor and neurodevelopment are relatively clear，but the adverse pregnancy events associated with it have not been conclusively confirmed，and the underlying pathological mechanisms remain insufficiently understood. Regarding treatment，the efficacy and timing of thyroid hormone replacement therapy remain controversial and require further investigation. This paper reviews the current state of research on IMH，aiming to raise awareness among clinicians，promote early identification and intervention，and reduce the occurrence of related adverse maternal and neonatal outcomes.

Key words: Isolated maternal hypothyroxinemia, Pregnancy complications, Iodine deficiency, Fetal neurodevelopment, Thyroxine

摘要： 妊娠期单纯低甲状腺素血症是妊娠期甲状腺激素缺乏的一种表现，可能会影响胎儿神经发育，增加流产、早产、妊娠期糖尿病的风险，但其具体机制、最佳治疗方案以及长期影响仍存在一定的不确定性。本文总结了妊娠期甲状腺激素水平与非妊娠期的差异，通过梳理相关文献，全面地分析了该疾病的病因、对母婴的影响及其治疗方案。本文认为缺碘及缺铁是妊娠期单纯低甲状腺素血症的主要病因，但关于胎盘生长因子等因素与该疾病的关联仍缺乏确凿证据。现阶段只有其对围产儿运动和神经发育产生的负面影响较为明确，其引发的不良妊娠事件尚未得到明确证实，相关病理机制更是未完全阐明。在治疗方面，甲状腺激素替代疗法的效果及治疗时机仍存在争议，亟需进一步研究。本文对该疾病的研究现状展开综述，旨在引起临床医生的高度关注，推动早期识别与干预，减少相关不良孕产结局的发生。

关键词: 妊娠期单纯低甲状腺素血症, 妊娠期并发症, 缺碘, 胎儿神经发育, 甲状腺素