Which of the following is a non-invasive test used to diagnose fetal Rh genotype in Rh D alloimmunization?: (A) Cell free fetal DNA, (B) Chorionic villus sampling, (C) Amniocentesis, (D) Middle cerebral aery peak systolic velocity
Answer is A. Fetal Rh D genotype assessment from maternal blood offers several potential benefits. Administration of anti-D immune globulin to an Rh D-negative pregnant woman carrying an Rh D-negative fetus can be eliminated.In the setting of Rh D alloimmunization, early identification of an Rh D-negative fetus can avoid unnecessary amniocentesis and/or serial fetal middle cerebral aery Doppler assessment. Rh D genotype evaluation using cell-free fetal DNA is done using real-time PCR to target multiple exons of the RHD gene(Ref: William's Obstetrics; 25th edition)