Identification of fetal growth retardation: comparison of Doppler waveform indices and serial ultrasound measurements of abdominal circumference and fetal weight.

OBJECTIVE

To compare the serial ultrasound assessment of abdominal circumference (AC) and fetal weight versus single values of umbilical artery pulsatility index (PI) and the aortic-middle cerebral PI ratio in the identification of fetal growth retardation (FGR).

METHODS

Serial AC measurements and estimates of weight were obtained in 104 small fetuses in the third trimester of pregnancy. These serial values (expressed as a change in standard deviation [SD] scores) were compared with the final value of AC and estimated fetal weight (EFW), umbilical artery PI, and the aortic-middle cerebral artery PI ratio (all expressed as SD scores) for their ability to predict a reduced neonatal ponderal index, mid-arm circumference-head circumference (HC) ratio, and skinfold thickness. Receiver-operating characteristic (ROC) curves were derived and the ultrasound measurements evaluated by calculating the areas under the ROC curves.

RESULTS

Serial estimates of fetal weight resulted in a significantly larger area under the ROC curve compared with the final aortic-middle cerebral PI ratio in the prediction of an abnormal mid-arm circumference-HC ratio and compared with the final AC, EFW, and umbilical artery PI in the prediction of all neonatal morphometric indices.

CONCLUSION

In small fetuses, fetal growth failure as determined by the serial assessment of AC and EFW was superior to the final AC and EFW, umbilical artery PI, and the aortic-middle cerebral PI ratio in the prediction of abnormal neonatal morphometry indicative of FGR.