Predicting neonatal weight of more than 4000 g using fetal abdominal circumference measurement by ultrasound at 38–40 weeks of pregnancy: A study in Iran

Abstract

To evaluate the value of fetal abdominal circumference (AC) measurement in pregnancies at 38-40 weeks of gestation and within 7 days of delivery to predict macrosomia. A prospective cohort study was performed on 276 pregnant women who were admitted to the labor ward with gestational age between 38-40 weeks. In all eligible women an ultrasonographic measurement of AC was performed. The women were then monitored up to delivery. All neonatal weights were recorded. The ACs were then evaluated for babies with a neonatal weight of more than 4000 g and babies with a neonatal weight of more than the 90th percentile for gestational age. Sixty-six neonates had a neonatal weight of more than 4000 g and 11 neonates had a birth weight of more than 4500 g. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for AC of more than 35 cm to predict a birth weight of more than 4000 g, were 97%, 54.5%, 40.3% and 98.3%, respectively, and of these 87.9%, 77.6%, 55.2% and 95.3% for AC of more than 36 cm. Percentages were 97.3%, 56.9%, 45.3% and 98.3%, for a birth weight of more than the 90th percentile for gestational age for AC of more than 35 cm, and 87.8%, 80.2%, 61.9% and 94.7% for AC of more than 36 cm for prediction of birth weight of more than the 90th percentile for gestational age. AC measurement at 38-40 weeks of gestation is a suitable index for estimating macrosomia.