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Ultrasound/Imaging

Poster Session 2

(374) Elevated Middle-Cerebral-Artery Peak-Systolic-Velocity (MCA-PSV) in non-anemic fetuses: Providing a better understanding of enigmatic MCA-PSV Dopplers

Tuesday, February 13, 2024
3:30 PM – 5:00 PM  
Location: Prince George's Exhibit Hall CDE, Lower Atrium Level
Objective:

An elevated middle cerebral artery peak systolic velocity (MCA-PSV) is a well-accepted tool for the diagnosis of fetal anemia with a progressive rise in MCA-PSV as anemia worsens . A value greater than 1.5 Multiple of Median (MoM) has a sensitivity of 100% and a false positive rate of 12% for the diagnosis of moderate to severe fetal anemia. High values of MCA-PSV may be due fetal behavioral state, fetal growth restriction, maternal diabetes, or other rare causes.

Our aim was to investigate the incidence, causes and outcome in fetuses with elevated MCA-PSV >1.5 MoM despite normal or near normal Hgb on fetal blood sampling (FBS).

Study Design:

An observational retrospective cohort study of all fetuses who underwent FBS due to MCA PSV >1.5 MoM at a tertiary fetal medicine center between 2007 and 2021. Fetuses were included if they had a no or mild anemia defined as Hgb deviation of less than 20 gr/L from a gestational age (GA) adjusted mean. Indications for Doppler assessment, causes of abnormal MCA PSV and neonatal outcomes were collected.

Results:

Overall, 383 fetuses had an MCA PSV >1.5 MoM and underwent subsequent FBS. Twenty-three (n=23, 6%) fetuses met inclusion criteria, and had normal Hgb or mild anemia at FBS.   The reasons for Doppler assessment included abnormal fetal surveillance or genetic anomalies (n=11), maternal isoimmunization (n=5), suspected antepartum hemorrhage (n=4) and non-indicated Doppler assessment (n=3). A cause for elevated MCA PSV other than moderate to severe anemia was eventually elucidated in 12 of the 23 cases (52.2%). Favorable perinatal outcomes were observed only in truly unexplained cases with no additional anomalies (n=11, 47.8%).

Conclusion:

Elevated MCA PSV >1.5 MoM appear in 6% of  pregnancies despite normal/near normal Hgb. Pregnancies with alternative causes for this false positive measurement are at risk for poor neonatal outcomes.