Bienstock J L, Holcroft C J, Althaus J
Division of Maternal-Fetal Medicine, Department of Gynecology and Obstetrics, The Johns Hopkins Medical Institutions, Baltimore, MD, USA.
Ultrasound Obstet Gynecol. 2008 May;31(5):517-9. doi: 10.1002/uog.5316.
To evaluate the predictive value of a combination of the 1 h 50-g glucose challenge test (GCT) and second-trimester ultrasound measurement of fetal abdominal circumference (AC) in identifying patients who will go on to deliver small-for-gestational age (SGA) neonates. The individual predictive power of these tests has been indicated by previous studies, but this study examines the combined use of these indicators in predicting SGA.
This retrospective cohort study included 576 consecutive patients with singleton gestations examined over a 3-year period. Patients' electronic medical records were abstracted to obtain the result of the GCT, the fetal AC measured by ultrasound examination between 18 and 22 weeks' gestation, and the birth weight. SGA and small AC were defined as birth weight or AC < 10(th) percentile for gestational age, according to published nomograms. A low GCT was defined as < 100 mg/dL. P < 0.05 was considered significant.
The prevalence of SGA in the study population was 8.7% (50/576). The frequency of SGA neonates was significantly higher in patients with a low GCT (27/207) in the second trimester than in those with a normal GCT (23/369) (13% vs. 6.2%, P = 0.005). Similarly, the frequency of SGA neonates was higher among patients with fetal AC < 10(th) percentile than among those with a normal fetal AC on second-trimester ultrasound examination (17% vs. 8%, P = 0.08), although this difference did not reach statistical significance. Of interest, among patients with both a small fetal AC and a low GCT the incidence of SGA neonates was 32% (6/19), but there were no SGA neonates among those with a small AC and normal GCT (0/17) (P = 0.014). Among patients with a small fetal AC the sensitivity of using low GCT to predict subsequent delivery of a SGA neonate was 100%, with a specificity of 57%, positive predictive value 32% and negative predictive value 100%.
Small AC on routine second-trimester anomaly sonogram should trigger a closer evaluation of maternal GCT. If the GCT is also low, more intensive surveillance for the possible development of a SGA infant is warranted.
评估1小时50克葡萄糖耐量试验（GCT）与孕中期超声测量胎儿腹围（AC）相结合，在识别将分娩小于胎龄（SGA）新生儿的患者中的预测价值。先前的研究已表明这些检查各自的预测能力，但本研究探讨这些指标联合用于预测SGA的情况。
这项回顾性队列研究纳入了3年内连续检查的576名单胎妊娠患者。提取患者的电子病历，以获取GCT结果、孕18至22周超声检查测量的胎儿AC以及出生体重。根据已发表的列线图，SGA和小AC定义为出生体重或AC低于胎龄的第10百分位数。低GCT定义为<100mg/dL。P<0.05被认为具有统计学意义。
研究人群中SGA的患病率为8.7%（50/576）。孕中期GCT低的患者（27/207）中SGA新生儿的频率显著高于GCT正常的患者（23/369）（13%对6.2%，P=0.005）。同样，孕中期超声检查时胎儿AC低于第10百分位数的患者中SGA新生儿的频率高于胎儿AC正常的患者（17%对8%，P=0.08），尽管这种差异未达到统计学意义。有趣的是，胎儿AC小且GCT低的患者中SGA新生儿的发生率为32%（6/19），但AC小且GCT正常的患者中无SGA新生儿（0/17）（P=0.014）。在胎儿AC小的患者中，使用低GCT预测随后分娩SGA新生儿的敏感性为100%，特异性为57%，阳性预测值为32%，阴性预测值为100%。
常规孕中期异常超声检查发现AC小应促使对孕妇GCT进行更密切评估。如果GCT也低，则有必要对可能发生SGA婴儿的情况进行更密切监测。
