Correlation of fetal blood vessel Doppler measurements with fetal anemia among Rhesus isoimmunized pregnancies after two intrauterine transfusions.

OBJECTIVE

To assess the correlation between fetal blood vessel Doppler measurements and fetal anemia among Rhesus isoimmunized pregnancies after two intrauterine transfusions as a potential guide to therapy.

METHODS

A prospective observational study was conducted among 30 women who attended a single hospital in India between April 2, 2015 and October 30, 2016. The participants underwent a third intrauterine transfusion based on a middle cerebral artery (MCA) peak systolic velocity (PSV) of greater than 1.50 multiples of the median (MoM). Cordocentesis was performed before the third intrauterine transfusion and hematocrit values correlated with the blood vessel Doppler measurements.

RESULTS

The MCA PSV MoM and fetal hematocrit MoM had a correlation coefficient of -0.43 (95% confidence interval -0.68 to 0.08; P=0.017). The sensitivity, specificity, positive predictive value, and negative predictive value were 68%, 57%, 83%, and 33%, respectively. The descending aorta PSV δ and fetal hematocrit δ had a correlation coefficient of -0.54 (95% confidence interval -0.75 to -0.23; P=0.001). An area under the curve of 0.80 (standard error 0.085; P=0.017) had 87% sensitivity and 57% specificity for diagnosing fetal anemia.

CONCLUSION

The descending aorta PSV could offer a useful diagnostic adjunct to MCA PSV after two intrauterine transfusions.