Middle cerebral artery Doppler reference centile charts for the prediction of fetal anemia in a population from India.

Abstract

To construct reference charts for the fetal middle cerebral artery (MCA) peak systolic velocity (PSV,) and the corresponding cord blood hemoglobin values at 24-40weeks of pregnancy for the identification of fetal anemia. In a cross-sectional study, 300 women with a pregnancy duration of 24-40weeks planned for delivery within 72hours underwent a Doppler study of the MCA and cord blood hemoglobin estimation at delivery. Regression analysis was used to construct reference charts. The validity of the charts was assessed in 40 fetuses from Rhesus-isoimmunized pregnancies. The MCA PSV and hemoglobin values increased with advancing gestational age. Multiples of the median (MOM) were calculated and reference charts were constructed for mild anemia (MCA PSV 1.29 MOM; hemoglobin 0.8 MOM), moderate anemia (MCA PSV 1.50 MOM; hemoglobin 0.6 MOM), and severe anemia (MCA PSV 1.55 MOM; hemoglobin 0.5 MOM). In the validation sample, the hemoglobin value estimated on the basis of the MCA PSV corresponded with the actual hemoglobin range in 90% of the fetuses. The sensitivity was 92% and the specificity was 95%. The constructed charts are suitable for the evaluation of fetal anemia in the regional population.