Detection of intrauterine fetal growth retardation with abdominal circumference and estimated fetal weight using cross-sectional growth curves.

The usefulness of a cross-sectional growth curve method in the detection of intrauterine growth retardation by ultrasonography was evaluated for abdominal circumference and estimated fetal weight. The patient sample consisted of 771 women with singleton pregnancy who delivered within seven days of an ultrasound scan. One hundred fifty-one (19.6%) women had infants with birth weight below the 10th percentile for menstrual age. Of these infants, 72.2% were symmetrically growth retarded on the basis of their neonatal ponderal index. The neonatal weight outcomes were correlated with the abdominal circumference and estimated fetal weight percentile values. Both measurements were more specific than sensitive and had much higher negative than positive predictive values. The sensitivity was influenced by menstrual age, and severity and type of intrauterine growth retardation. Overall, estimated fetal weight was more accurate than abdominal circumference, but the difference was too small to be clinically important. Both measurements were better suited to confirm than to detect, exclude, or predict intrauterine growth retardation. Normal results predicted a normal neonatal weight outcome with a very high probability when the prevalence of the condition was low. In spite of the limitations of the cross-sectional method, both tests had strengths that can be advantageously used to enhance clinical decision making in the management of intrauterine growth retardation.