A case of non-immune fetal hydrops, diagnosed as mucopolysaccharidosis VII with hypoalbuminemia, was treated in utero with albumin transfusions via cordocentesis on five occasions. Blood samples were taken for analysis of full blood count and blood gases before and after the transfusions. Pulsed Doppler ultrasound examinations of the arterial waveform were performed in the umbilical arteries and the descending fetal aorta and analyzed for the pulsatility index (PI). The hemoglobin concentration and the hematocrit decreased from Ill ± 5 g/l and 0.335 ± 0.008 to 95 ± 5 g/l and 0.282 ± 0.023 (mean ± SD), respectively, after the transfusions. The calculated blood volume increased more than the given volume, indicating an autotransfusion causing additional plasma volume expansion. The blood gases were not significantly changed by transfusion. The PI decreased both in the umbilical arteries (p < 0.05) and the descending fetal aorta, indicating peripheral vasodilatation. A positive correlation was found between the umbilical artery PI and the hematocrit before and after the albumin transfusion (r = 0.59; p < 0.05). This relation could be due to covariation with other factors, e.g. peripheral vasodilatation secondary to the increased blood volume and the puncture of the umbilical vein itself. No improvement of the hydrops was seen after the albumin transfusions. The fetus died in utero during spontaneous labor after 30 gestational w