INTRODUCTION Peak systolic velocity (PSV) of the middle cerebral artery (MCA) shows 100% sensitivity for predicting fetal anemia before the first intrauterine transfusion (IUT). However, its ability to predict subsequent… Click to show full abstract
INTRODUCTION Peak systolic velocity (PSV) of the middle cerebral artery (MCA) shows 100% sensitivity for predicting fetal anemia before the first intrauterine transfusion (IUT). However, its ability to predict subsequent transfusions has remained mostly controversial. OBJECTIVES To assess if there is a need to change the threshold of MCA-PSV from 1.5 to 1.69 multiples of the median (MoM) to predict fetal anemia and the need for subsequent IUT. METHODS This is a retrospective audit, wherein case records of mothers who underwent IUT at the Bangalore Fetal Medicine Centre between April 2008 and May 2017 were reviewed; 86 cases were included, and the data were analyzed using MS Excel. The MCA-PSV and pretransfusion Hb were converted into MoM. 40 fetuses that had more than 1 IUT were included in the analysis. -Results: 31/40 fetuses that had >1 IUT had an MCA-PSV >1.5 MoM, of which 29 were anemic according to the post-IUT Hb MoM. 20/29 (69%) had an MCA-PSV >1.69, whereas 9/29 (31%) had an MCA-PSV between 1.5 and 1.69 MoM. Our study shows that changing the MCA-PSV threshold from 1.5 to 1.69 MoM will reduce the detection of fetal anemia and hence the need for repeat IUT by 31%. CONCLUSIONS Increasing the fetal MCA-PSV threshold from 1.5 to 1.69 will miss out one-third of the fetuses that will require a 2nd, 3rd, or 4th IUT. This is more relevant in geographical areas where the parents must travel long distances for IUTs, which are performed in tertiary fetal care centers.
               
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