Fetal Monitoring: Doppler Ultrasonography
Fetal monitoring is used to assess the severity of HDFN and determine whether antenatal transfusion Is warranted.
Monitoring can be accomplished by:
- Doppler ultrasonography
Doppler sonography is a type of ultrasound that detects and measures blood flow.
As related to HDFN, Doppler sonography can be done beginning at 18 weeks. It measures the peak velocity of systolic blood flow in the fetal middle cerebral artery and is used to predict severity of fetal anemia. The hypothesis is that a faster rate of blood flow indicates a more severely anemic fetus, with severe anemia being an indicator of fetal hydrops.
Because Doppler sonography is noninvasive and a safer alternative to amniocentesis, it has largely replaced serial amniocentesis for predicting severity of HDFN.