A Rh negative G4P3+O has an antibody level of 15 IU/ml (IAT 1 :32) at 27 weeks.What is the most appropriate next step in the management?
Estimate the amniotic fluid bilirubin levels Estimate the fetal hemoglobin levels by cordocentesis Estimate the middle cerebral artery peak systolic velocity Perform intrauterine transfusion