Brandt Justin S, Bastek Jamie A, Wang Eileen, Purisch Stephanie, Schwartz Nadav
Maternal and Child Health Research Program, Department of Obstetrics and Gynecology, Center for Research on Reproduction and Women's Health, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania USA.
J Ultrasound Med. 2016 May;35(5):989-97. doi: 10.7863/ultra.15.06095. Epub 2016 Apr 12.
Previous studies have demonstrated an association between adverse obstetric outcomes, such as preterm birth, and in utero inflammation. The fetal thymus, which can be visualized in the anterior mediastinum on obstetric sonography, may involute in response to such inflammation and thus may identify pregnancies at increased risk for these outcomes. We therefore sought to determine whether second-trimester fetal thymus measurements are associated with preterm birth.
Transabdominal fetal thymus measurements were prospectively obtained in singleton pregnancies at gestational ages of 18 weeks to 23 weeks 6 days during a 5-month period. The transverse and anterorposterior thymus diameters and the thymic-thoracic ratio were measured. Delivery outcomes were collected from our clinical database. The primary outcome was preterm birth, which we defined as delivery between 24 weeks and 36 weeks 6 days. Small for gestational age (SGA) and pregnancy-related hypertension, which are adverse obstetric outcomes that may also be associated with in utero inflammation, were included as secondary outcomes.
We included 520 patients with thymus measurements and obstetric outcome data. The prevalence of preterm birth was 12.3% (n = 64). None of the thymus measurements were associated with preterm birth. Similarly, there was no association between thymus measurements and SGA or pregnancy-related hypertension.
Sonographic assessment of the second-trimester fetal thymus did not identify patients at increased risk for preterm birth, SGA, and pregnancy-related hypertension. Routine thymus measurements during the second-trimester anatomic scan are not clinically useful for prediction of preterm birth and other adverse outcomes.
既往研究已证实不良产科结局，如早产，与宫内炎症之间存在关联。胎儿胸腺可在产科超声检查中于前纵隔显影，可能会因这种炎症而萎缩，因此可能识别出发生这些结局风险增加的妊娠。因此，我们试图确定孕中期胎儿胸腺测量值是否与早产有关。
在5个月期间，前瞻性地获取孕龄为18周 至23周6天的单胎妊娠经腹胎儿胸腺测量值。测量胸腺的横径和前后径以及胸腺 - 胸廓比率。从我们的临床数据库收集分娩结局。主要结局是早产，我们将其定义为在24周 至36周6天之间分娩。小于胎龄儿（SGA）和妊娠相关高血压是也可能与宫内炎症相关的不良产科结局，作为次要结局纳入。
我们纳入了520例有胸腺测量值和产科结局数据的患者。早产的患病率为12.3%（n = 64）。胸腺测量值均与早产无关。同样，胸腺测量值与SGA或妊娠相关高血压之间也无关联。
孕中期胎儿胸腺的超声评估未识别出早产、SGA和妊娠相关高血压风险增加的患者。孕中期解剖扫描期间常规胸腺测量对早产和其他不良结局的预测在临床上并无用处。
