The problem of studying post partum anti-D-prophylaxis in Rh-negative women

To check the efficiency of the postpartum Anti-D-prophylaxis we conducted a post-vaccination study on 82 Rhesus-negative women who had delivered a Rhesus-positive child. We could demonstrate that in only five per cent of the women no free Anti-D could be found by Coombs test 48 hours after vaccination with 300 mu g anti-D i. m. (Rhesogam (R)). Failure of prophylaxis was positivly correlated to overweight. The indirect Coombs-test is an appropriate method to check the effect of Rhesus-prophylaxis. We recommend to primarily increase the dose of anti-D in all patients whose body weight is higher than 90 kg.