Abstract
<b><i>Introduction:</i></b> Our aim was to investigate the incidence, comorbidities, and outcomes of fetuses with an elevated middle cerebral artery peak systolic velocity (MCA-PSV) >1.5 multiples of median (MoM), despite normal hemoglobin (Hgb) levels on fetal blood sampling (FBS). <b><i>Methods:</i></b> A single-center observational retrospective cohort study of all fetuses undergoing FBS and MCA-PSV >1.5 MoM. Only those fetuses with no or mild anemia were included. Indications for Doppler assessment, associated anomalies, and neonatal outcomes were collected. <b><i>Results:</i></b> Overall, 383 fetuses had an MCA-PSV >1.5 MoM and underwent FBS. Twenty-three (6%) fetuses met our inclusion criteria and had no or only mild anemia. Associations with elevated MCA-PSV were elucidated in 12 of the 23 cases (52.2%) and included mild anemia (<i>n</i> = 2), intracranial hemorrhage (<i>n</i> = 3), genetic disease (<i>n</i> = 1), idiopathic nonimmune hydrops (NIH, <i>n</i> = 1), hypoxic-ischemic encephalopathy (<i>n</i> = 1), maternal and or fetal acidosis (<i>n</i> = 3), and fetal growth restriction (<i>n</i> = 1). Favorable perinatal outcomes were observed in truly unexplained 11 cases with no additional anomalies (47.8%). <b><i>Conclusion:</i></b> Elevated MCA-PSV >1.5 MoM with normal Hgb levels is seen in 6% of pregnancies undergoing FBS and is often associated with other significant maternal or fetal problems. Those with unexplained and isolated MCA-PSV elevation have normal outcomes.