Feto-maternal blood immunization
Definition and Pathophysiology
It is the synthesis by the mother of antibodies against the fetal blood elements (erythrocytes fetal platelets, ...). The result is a hemolysis of fetal blood elements. Maternal antibody production can occur whenever there is introduction of red blood cells "foreign" transfusion, pregnancy, ...
It occurs in Rh-negative women (Rh-) carrying a Rh positive fetus (Rh)..During a first pregnancy, there may be passage of fetal erythrocytes (Rh) in the maternal circulation.The mother will then produce antibodies to fetal red blood cells to the presence of foreign elements in blood circulation.This production of antibodies will have no effect on this pregnancy because they can not pass the placental barrier.However during a subsequent pregnancy of a fetus Rh, there will be a significant and rapid synthesis of antibodies, which passes the placental barrier, and therefore that will bind to fetal erythrocytes and lyse. The result is a fetal anemia which may cause generalized fetal edema (hydrops fetalis) which can lead to death. The other consequence is the presence of kernicterus (different from neonatal jaundice Benin) at birth.Screening
It is therefore necessary to achieve screening of anti fetus maternal antibodies This screening is done by looking for irregular antibodies (DI) during pregnancy. It is legally required:-In women who are Rh-: at first consultation and 6th, 8th, 9th month of pregnancy-In women who are Rh + a t the first consultation-In women who are RH + with a history / first consultation, 6th, 8th, 9th month of pregnancy.Prevention
It is systematically performed at the slightest risk of fetal erythrocytes passing into the bloodstream of an Rh-- woman.What are the risks?1st TRIMESTER-Ectopic pregnancy-Miscarriage-Abortion-Amniocentesis-Strapping-Any episode of metrorrhagia2nd TRIMESTER-Amniocentesis, cordocentesis-Medical termination of pregnancy-Abdominopelvic trauma-Any episode of metrorrhagia3rd TRIMESTER-Placenta previa-Amniocentesis-Trauma abdominal - pelvic-Fetal death in utero-Any episode of metrorrhagia-After delivery, if the child is Rh-Methods of preventionThe goal is to deliver as quickly as possible to the mother of anti-D Gamma globulins that will neutralize the Rh+ fetal erythrocytes passed into the maternal circulation . Gamma globulins are injected intravenously at best within 72 hours following a risky situation allo immunization
Victor Hugo