The decline in Rh hemolytic disease: Should Rh prophylaxis get all the credit?

Abstract

Objectives. This study sought to quantify the magnitude of Rh disease reduction occurring secondary to Rh prophylaxis and other determinants. Methods. Outcomes considered included maternal Rh sensitization, neonatal Rh disease, and perinatal deaths from Rh disease. Analysis was based on Poisson regression modeling of ecological data form Manitoba, Canada, and conditional probability modeling. Results. The ecological analysis showed that changes in birth order and Rh prophylaxis resulted in 24% (95% confidence interval [CI] = 1%, 42%) and 69% (95% CI = 61%, 76%), decrease respectively, in Rh sensitizations (D and non-D) in Manitoba between 1963 and 1988, Rh prophylaxis, and nonprogram factors were responsible for 83% (95% CI = 44%, 95%) and 78% (95% CI = 42%, 91%), respectively, of the reduction in perinatal deaths from Rh disease. Similar results were obtained with conditional probability modeling, which also provided estimates for the effects of changes in abortion rates and racial composition. Conclusions, In addition Rh prophylaxis, changes in other determinants were responsible for an important fraction of the decline in Rh disease. These results provide a historical perspective on the conquest of Rh disease and also have important implication for public health policy, particularly in developing countries.