Middle Cerebral Artery Peak Systolic Velocity of Healthy Fetuses in the First Half of Pregnancy

Abstract

The purpose of this study was to establish normative data of middle cerebral artery (MCA) peak systolic velocity (PSV) in the first half of normal pregnancies (11-22 weeks). A prospective cross-sectional descriptive study was conducted in which low-risk pregnant women whose pregnancies were singleton with accurate gestational age were recruited into the study. All neonates were subsequently proven to be healthy at birth. The sonographic measurements of MCA PSV were performed by the same examiner with a high-resolution machine. The total number of measurements was 410, and the number of measurements for each gestational week ranged from 30 to 40. The best regression model between gestational week and placental thickness was observed to be a linear function, and reference curves were constructed. The results showed a continuous increase in MCA PSV over the period from 11 to 22 weeks. During the period of study, 3 fetuses with hemoglobin Bart disease in the first half of pregnancy were encountered, and all of them had PSV of greater than the 95th percentile as well as 1.5 multiples of the median for each gestational week. A nomogram of MCA PSV for each gestational age from 11 to 22 weeks was constructed. These reference ranges may be useful noninvasive tools in risk assessment for fetal anemia in early pregnancy, especially due to hemoglobin Bart disease.