Epidemiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, MD 20852, USA.
Ultrasound Obstet Gynecol. 2011 Jul;38(1):62-6. doi: 10.1002/uog.8902. Epub 2011 Jun 2.
Being small-for-gestational age (SGA) is associated with an increased risk of morbidity, but questions remain about how best to diagnose SGA, and thus, predict poor health consequences. The authors sought to compare an individualized reference for defining SGA with simple birth weight-based and ultrasound-based references applied to birth weight in predicting poor cognitive development at age five.
The authors used data from the Successive SGA Births Study, a prospective study including 699 Alabaman and 618 Scandinavian women recruited from 1986 to 1988, and whose children had cognitive development scores measured at age five using the Wechsler Preschool and Primary Scale of Intelligence-Revised Intelligence Quotient. Sensitivity, specificity and positive predictive value (PPV) were estimated for each reference applied to birth weight using adverse cognitive development (score < 10(th) percentile) as the outcome. Relative risk of poor neurodevelopment was calculated, comparing infants classified as SGA by either the individualized or the simple ultrasound-based reference with infants not classified as SGA.
The individualized reference had higher specificity and PPV in predicting poor neurodevelopment. Neonates defined as SGA by the individualized reference alone had a higher risk (RR=2.20, 95% CI: 1.20, 4.00) of poor cognitive outcome, while those identified by the ultrasound-based reference alone did not (RR=0.95, 95% CI: 0.45, 2.01). None of the references could predict poor neurodevelopment well at age five.
The individualized birth weight reference modestly outperforms the simple ultrasound-based reference in identifying SGA infants with poor child neurodevelopment. However, neither reference can predict child neurodevelopment well.
胎儿生长受限（SGA）与发病率增加相关，但仍存在一些问题，即如何最好地诊断 SGA，从而预测不良健康后果。作者试图比较个体参考定义 SGA 与简单的基于出生体重和超声的参考应用于出生体重预测五岁时认知发育不良。
作者使用了来自连续 SGA 出生研究的数据，这是一项前瞻性研究，包括 1986 年至 1988 年从阿拉巴马州和斯堪的纳维亚招募的 699 名和 618 名女性，其子女在五岁时使用韦氏学龄前和小学量表修订版智商测试进行认知发展评分。使用不良认知发育（得分<第 10 百分位数）作为结局，估计每个参考应用于出生体重的敏感性、特异性和阳性预测值（PPV）。通过比较通过个体化或简单超声参考定义为 SGA 的婴儿与未分类为 SGA 的婴儿，计算不良神经发育的相对风险。
个体化参考在预测不良神经发育方面具有更高的特异性和 PPV。仅通过个体化参考定义为 SGA 的新生儿认知结局不良的风险较高（RR=2.20，95%CI：1.20，4.00），而仅通过超声参考定义为 SGA 的新生儿则没有（RR=0.95，95%CI：0.45，2.01）。没有任何参考可以很好地预测五岁时的不良神经发育。
个体化出生体重参考在识别认知发育不良的 SGA 婴儿方面略优于简单的基于超声的参考。然而，这两种参考都不能很好地预测儿童神经发育。
