Prediction of fetal outcome in small for gestational age fetuses: comparison of Doppler measurements obtained from different fetal vessels.

Blood flow velocity waveforms were recorded from different vascular districts including umbilical artery, descending aorta, renal artery, internal carotid artery and middle cerebral artery in a population of 120 small for gestational age fetuses free from structural and chromosomal abnormalities. The pulsatility index from each vessel as well as the ratios between the pulsatility indices from peripheral and cerebral vessels were calculated and related to perinatal outcome. The pulsatility index of middle cerebral artery resulted the most efficient measurement to predict the development of perinatal adverse outcome when each vessel was considered singularly, however, better results were achieved when the ratios between pulsatility indices were related to perinatal outcome; this is mot evident for the ratio between the pulsatility indices of umbilical artery and middle cerebral artery. Our results suggest the usefulness of this ratio in differentiating small for gestational age fetuses at risk of unfavorable outcome.