Optimal Interval between Middle Cerebral Artery Velocity Measurements when Monitoring Pregnancies Complicated by Red Cell Alloimmunization

Abstract

To evaluate the optimal interval between middle cerebral artery (MCA) Doppler measurements when monitoring pregnancies complicated by red cell alloimmunization. Thirty-nine fetal blood samplings (FBS) performed on 24 pregnant women with red blood cell alloimmunization followed up using both MCA peak systolic velocity and time-averaged mean velocity measurements on weekly basis. In total, 65.5 and 37.5% of women with moderate or severe fetal anemia had abnormal MCA Doppler values 1 and 2 weeks, respectively, before FBS was performed. A weekly assessment of women at risk for fetal anemia is optimal in most of the cases even though 35.5% of cases of moderate or severe fetal anemia are expected to have normal Doppler measurements the week before the decision of doing an FBS is made.