Changes in blood flow velocity waveforms are measured by pulsed Doppler in the umbilical and fetal cerebral arteries- Doppler US for fetal assessment in high risk pregnancy- umbilical and cerebral Doppler Velocimetry measurement-
It is a sort of antepartum fetal surveillance, depending upon what is done for your patient, you would have to code.
The one you are looking for is done in Doppler velocityy measurement. That is through the fetal umbilical artery Doppler velocimetry- CPT 76820; Fetal Middle cerebral artery Doppler Velocimetry CPT 76821.
Fetal umbilical artery DV 76820 is considered medically necessary for : fetal growth retardation less than 10th percentile Or monochorionic /diamniotic twins with growth discripancy more than 20%, Twin to Twin Transfusion syndrome, or Oligohydramnios with AFI less than 7cm.
It can be peroformed more frequently if there is DOCUMENTATION OF ABSENT END DIASTOLIC VELOCITY /FLOW, RESERVED FLOW OR FLOW INDEX MORE THAN 2SD , ABOVE THE MEAN, FOR A GIVEN GESTATIONAL AGE.
I hope this helps you