DOPPLER FLOW VELOCIMETRY OF THE SPLENIC ARTERY IN THE HUMAN FETUS - IS IT A MARKER OF CHRONIC HYPOXIA

OBJECTIVE: The aim of this investigation was to describe splenic arter y flow velocity waveforms in the appropriate- and small-for-gestationa l-age human fetus. STUDY DESIGN: Splenic artery flow velocity waveform s were prospectively obtained from 95 appropriate- and 15 small-for-ge stational-age fetuses with pursed Doppler ultrasonography. The resista nce index was used to quantify the Doppler waveform. RESULTS: A second -degree polynomial model expressed the changes of the resistance index in appropriate-for-gestational-age fetuses with advancing gestation ( y = 0.057x [Weeks] - 0.001x(2), r = 0.53, p < 0.001). In 14 of 15 (93% ) small-for-gestational-age fetuses the splenic artery resistance inde x was below the mean for gestational age. In five of 15 (33%) small-fo r-gestational-age fetuses the resistance index of the splenic artery w as <2 SEMs. A trend toward a higher hematocrit was noted in the five f etuses with splenic artery resistance index values <2 SEMs (50.2%) com pared with other small-for-gestational-age fetuses (43.0%). CONCLUSION : Our results suggest that some small-for-gestational-age fetuses have decreased resistance at the level of the splenic artery. We postulate that the increased erythropoietin level, stimulated by hypoxia, resul ts in decreased resistance at the level of the splenic artery in small -for-gestational-age fetuses. Finally management of the small-for-gest ational-age fetus may be aided by the study of the splenic artery wave forms.