RESUMO
Although very rare, red-cell immunization is a main factor of hemolytic fetal anemia and severe neonatal jaundice. We emphasize on the prevention of immunization in different situations of feto maternal bleeding by early intravenous injection of 200 at 300 IU or more depending on the term of pregnancy, the circumstances and results of the Kleihauer's test. Prophylaxis conrresponds a systematic intramuscular injection of 300 IU immunoglobulin [Natead [R]] at 28 WA, is performed in many countries. This measure implies information and rigor from Perinatal's professional. If this systematic prophylaxis was conducted, it is not necessary to repeat the IAR until the birth. But if the patient has not received the injection of 28 WA, IAR of the 8[th] month must be maintained