背景：不同类型的甲状腺癌(DTC)在生育年龄的妇女中越来越普遍。然而，妊娠是否增加了治疗后DTC进展/复发的风险仍然有争议。本研究旨在评估曾接受DTC初次治疗的患者中妊娠与进展风险的关联。方法：这是一项回顾性队列研究，随访了北京大学第三医院于2012年1月至2022年12月间的123名妊娠妇女和1376名未妊娠妇女。为了控制混杂因素的影响，我们使用倾向性评分匹配（PSM）仔细匹配了妊娠组（n=107）和非妊娠组（n=298）的基线特征。结果：基线时，妊娠组和非妊娠组在所有匹配变量上是均衡的。随访时，两组DTC进展的百分比分别为12(11.8%)和47(15.8%)。回归模型表明没有证据表明妊娠与进展风险有关（奥区比：0.74，95%置信区间：0.37-1.50；p=0.404），并且在长期/短期随访和其他亚组变量中保持一致。我们发现，治疗与妊娠之间的时间间隔越短，DTC进展的风险越高（ptrend=0.019）。结论：妊娠妇女DTC进展的风险并不高于良好匹配的非妊娠妇女。对于曾接受DTC治疗的年轻妇女，疾病进展可能不会影响将来的生育计划，但与立刻怀孕相比，至少等待1年似乎更安全。

Background: Differentiated thyroid cancer (DTC) is increasingly common in women of reproductive age. However, whether pregnancy increases the risk of DTC progression/recurrence after treatment remains controversial. The study aimed to assess the association of pregnancy with risk of progression in patients previously treated for DTC. Methods: This was a retrospective cohort study following 123 pregnant women and 1376 nonpregnant women at Peking University Third Hospital after initial treatment for DTC between January 2012 and December 2022. To control the effect of confounding, we carefully matched pregnancy (n = 107) and nonpregnancy groups (n = 298) in terms of baseline characteristics by using propensity score matching (PSM). Results: At baseline, the pregnancy and nonpregnancy groups were balanced in all matched variables. At follow-up, the percentage of DTC progression in the two groups was 12 (11.8%) and 47 (15.8%), respectively. Regression models showed no evidence of association of pregnancy with the risk of progression (odds ratio: 0.74 and 95% confidence interval: 0.37-1.50; p = 0.404), and remained consistent across long/short follow-up and other subgroup variables. We found that the shorter the time interval between treatment and pregnancy, the higher the risk of DTC progression (ptrend = 0.019). Conclusions: The risk of DTC progression in pregnant women was not higher than that in the well-matched, nonpregnant women. For young women previously treated for DTC, disease progression might not be a concern for their future pregnancy plan, but it seems safer to wait at least 1 year before pregnancy compared with immediate pregnancy.