OBJECTIVE: Non-invasive fetal Rhesus (Rh) D genotyping, using cell-free fetal 
DNA (cffDNA) in the maternal blood, allows targeted antenatal anti-RhD 
prophylaxis in unsensitized RhD-negative pregnant women. The purpose of this 
study was to determine the cost and benefit of this approach as compared to 
routine antenatal anti-RhD prophylaxis for all unsensitized RhD-negative 
pregnant women, as is the current policy in the province of Alberta, Canada.
METHODS: This study was a decision analysis based on a theoretical population 
representing the total number of pregnancies in Alberta over a 1-year period 
(n = 69 286). A decision tree was created that outlined targeted prophylaxis for 
unsensitized RhD-negative pregnant women screened for cffDNA (targeted group) vs 
routine prophylaxis for all unsensitized RhD-negative pregnant women (routine 
group). Probabilities at each decision point and costs associated with each 
resource were calculated from local clinical and administrative data. Outcomes 
measured were cost, number of women sensitized and doses of Rh immunoglobulin 
(RhIG) administered.
RESULTS: The estimated cost per pregnancy for the routine group was 71.43 
compared with 67.20 Canadian dollars in the targeted group. The sensitization 
rates per RhD-negative pregnancy were equal, at 0.0012, for the current and 
targeted programs. Implementing targeted antenatal anti-RhD prophylaxis would 
save 4072 doses (20.1%) of RhIG over a 1-year period in Alberta when compared to 
the current program.
CONCLUSIONS: These data support the feasibility of a targeted antenatal anti-RhD 
prophylaxis program, at a lower cost than that of the existing routine 
prophylaxis program, with no increased risk of sensitization.