Methodology This will be a randomized and double-blind clinical trial essay . The mothers will be approached during the prenatal treatment, after being diagnosed as carriers of hemolytic disease due to Rh alloimmunization. The research will be presented and the mother/family will be invited to participate in the study. The informed consent term will be presented to the mother/family and they will be allowed some time to decide. If they are accepted in the study they will receive a questionnaire on the issues related to the possible reasons of sensitization.