中文摘要：

目的分析甲状腺癌术后妊娠期甲状腺素水平的调控过程，旨在降低母体甲状腺功能减退继发的胎儿异常发生率。方法回顾性分析20例甲状腺癌术后妊娠妇女甲状腺激素水平的调控过程，通过每月监测其甲状腺功能，了解左旋甲状腺激素（优甲乐）增加剂量和目标TSH水平。结果20例妊娠妇女孕21次，1例妊娠2次，第1次孕早期流产，20例优甲乐的基础剂量均为100μg，以12．5μg为调整增量，目标TSH水平设为0．10—0．25mU／ml。20例优甲乐剂量平均增加50μg，即增加了基础剂量的50％。在孕16周左右TSH水平达到平衡，直至分娩。所有胎儿均健康，发育良好；所有20位妇女产后均规律随访，时间平均5年（6个月～10年），无复发。结论甲状腺癌术后妊娠，应定期监测甲状腺功能，优甲乐以12．5μg为调整剂量，将母体TSH水平控制在0．10—0．25mU／ml，既保证胎儿健康发育，又抑制母体肿瘤生长。

英文摘要：

Objective Hypothyroidism during pregnancy has been associated with impaired cognitive development and increased fetal mortality. In this retrospective study we attempt to identify the timing and adjustment of levothyroxine during pregnancy. Methods 20 women planning pregnancy after thyroideetomy because of thyroid cancer were observed before and throughout their pregnancies. Their thyroid function was measured before conception, and approximately every 4 weeks during pregnancy. The dose of levothyroxine was increased to maintain the thyrotropin concentration at preconception values throughout pregnancy. Results 21 pregnancies occurred in the 20 women and resulted in 20 full-term births. One woman had abortion. Their basal dose was all 100 μg. The dose increased by 12.5 μg a time to target the thyrotropin concentrations （0.1 -0.25 mU/ml）. The mean levothyroxine requirement increased 50 percent during the first half of pregnancy and plateaued by the 16th week. This increased dose was required until delivery. All the newborns and their mothers were healthy according to the follow-up. Conclusions We propose that women after thyroid cancer surgery should increase levothyroxine dose as soon as pregnancy is confirmed. Thereafter, serum thyrotropin level should be monitored and the levothyroxine dose adjusted accordingly. The adjustment dose is set at 12.5 μg and the maternal thyrotropin concentration is between 0.10 and 0.25 mU/ml, which guarantees healthy growth of fetus while suppresses thyroid tumor growth simultaneously.