Which screening method is recommended for detecting fetal anemia after maternal exposure to Parvovirus B19?

The recommended method for detecting fetal anemia after maternal exposure to Parvovirus B19 is MCA Doppler ultrasound. This technique assesses the peak systolic velocity of blood flow in the middle cerebral artery (MCA), which can indicate anemia in the fetus. When the fetus becomes anemic, the heart has to work harder to pump blood to the brain, resulting in an increased velocity of blood flow within the MCA. This method is non-invasive, widely available, and provides real-time assessments, making it ideal for monitoring fetal conditions such as anemia caused by infections like Parvovirus B19.

In contrast, although amniocentesis with PCR could detect the presence of Parvovirus B19 and assess other conditions, it is an invasive procedure and does not directly measure fetal anemia. Fetal MRI is primarily used for evaluating structural anomalies and may not effectively identify anemia. A maternal blood test can check for maternal antibodies or viral load but does not provide direct evidence of anemia in the fetus. Therefore, MCA Doppler ultrasound is the most suitable and effective screening method in this context.