Middle cerebral artery Doppler velocimetric assessment in two cases of hydrops fetalis without fetal anaemia.

OBJECTIVES

Raised middle cerebral artery (MCA) Doppler velocity has been shown to be highly predictive of moderate to severe fetal anaemia. We present two false-positive cases of raised MCA Doppler velocity in non-immune hydropic fetuses.

METHODS

In both cases, routine investigations for fetal hydrops, as well as detailed ultrasound scanning and MCA peak-systolic velocity Doppler assessment (maximum velocity taken at zero degrees to the vessel), were performed. Fetal blood sampling was carried out at the same visit.

RESULTS

MCA peak-systolic velocity values greater than 1.50 MoM for gestation were found in both cases. However, both fetuses had normal haemoglobin values and haematocrits. Both fetuses died in utero soon after diagnosis.

CONCLUSIONS

A raised MCA velocity in a hydropic fetus may not always be due to fetal anaemia, rather it may indicate a fetus in poor condition perhaps due to cardiovascular decompensation and redistribution of blood to the fetal brain.