OC171: Prediction of fetal anaemia in the survivor in cases with intrauterine death of one monochorionic twin

Abstract

To assess the value of the fetal middle cerebral artery peak systolic velocity (MCA-PSV) in the prediction of anemia within 24 hours of the death of one monochorionic twin in twin-to-twin-transfusion syndrome, and to establish the correlation between MCA-PSV and hemoglobin concentration in fetuses at risk of acute anemia. Doppler examination of the MCA-PSV was performed in twenty monochorionic survivors of pregnancies complicated by TTTS that occurred between 20 and 34 weeks of gestation. Doppler examination was performed before cordocentesis and after intra-uterine transfusion when appropriate. Both hemoglobin concentration and MCA-PSV were expressed in multiples of the median (MoM). Severe anemia was defined as Hb < 0.55 MoM and we used the cut-off point of 1.50 times the median values at any gestational age to calculate the sensitivity and specificity of MCA-PSV in detecting moderate or severe anemia. Fetal anemia was confirmed in ten of twenty fetuses. We performed seven intra-uterine transfusions. The sensitivity and specificity of MCA-PSV in predicting severe fetal anemia were of 90.% with a false negative rate of 10%. The correlation between peak systolic velocity and hemoglobin concentration both pre- and post-transfusion was evaluated by regression analysis and was strongly significant. In fetuses at risk of acute anemia, the measurement of MCA-PSV was found to be a reliable non invasive diagnostic tool and may be helpful in counselling and planning invasive assessment.