Blood flow velocity waveforms of the abdominal arteries in appropriate- and small-for-gestational-age fetuses

The aim of this study was to describe flow velocity waveforms of abdominal arteries in the appropriate- and small-for-gestational-age fetus. Splenic artery, superior mesenteric artery, hepatic artery and renal artery velocity waveforms were obtained from 57 appropriate-for-gestational-age and nine small-for-gestational-age fetuses with color flow Doppler ultrasonography. The pulsatility index was used to quantify the arterial waveforms. Repeated measure analysis of variance indicated significant differences in the pulsatility index values in both the appropriate-for-gestational-age and small-for-gestational-age fetuses. A multiple comparison test revealed a significantly lower value for the pulsatility index in the splenic artery when compared to that of the other vessels for both the appropriate- and small-for-gestational-age fetuses. In the small-for-gestational-age fetuses, a lower pulsatility index value was observed at the superior mesenteric artery level when compared to the renal artery. Because of its lower frequency of successful insonation, the hepatic artery was not considered for the analysis. In the normal fetus, the splenic artery had the lowest pulsatility index when compared to the other arteries we investigated. This difference remained in small-for-gestational-age fetuses, reflecting a lower vascular resistance at the fetal spleen in both normal and small-for-gestational-age fetuses. It appears that in small-for-gestational-age fetuses the renal artery has a higher pulsatility index than the superior mesenteric artery, suggesting a preferential distribution of blood flow to the bowel.