The Evaluation and Interpretation of Ultrasonic Assessment of Fetal Growth

HE ULTRASONIC measurement of fetal structures for comparison with standard models of growth is a technique routinely used to assess risk of a fetus or neonate to be delivered small for its gestational age and to experience the complications associated with intrauterine growth retardation.l~15 While this type of evaluation is commonly performed with a high degree for clinical reassurance for the patient and her physician, the clinical interpretation of fetal growth is complex and currently involves primarily individualized approaches. Most clinicians have not evaluated the sources of the various graphs and tables that they utilize to establish their diagnosis of normal growth. The varying criteria of patient selection in individual studies, different techniques of statistical analysis, and multiple criteria for evaluation of outcome have made interpretation difficult when comparison of standard reference models is attempted. The purpose of this article is to discuss important variables used in the development of models for the description of the growth of fetal structures and for the establishment of neonatal growth curves, which frequently represent outcome criteria used in the evaluation of fetal measurements. The clinical approach, which is utilized at our institution for assessing the fetal risk for abnormal fetal growth from single or serial ultrasound examinations, will be described.