Background: Hemolytic disease of the fetus and newborn is a disease resulting from maternal red cell alloantibodies directed against fetal red cells. It´s mostly due to Rh (D), ABO and rarely due to other minor blood group incompatibility. The advent of RhD immunoglobulin prophylaxis to prevent maternal Rh-D alloimmunisation has reduced the incidence of this condition and its associated poor outcomes (including neonatal anemia, hyperbilirubinemia and perinatal death).Case Presentation Summary: The authors report a family case of Rh alloimmunization due to anti-c antibodies. It was a female term newborn, born at 37 weeks of gestation to a 5th gravida mother, by induced labour. Apgars were 9/10/10. Antenatal period was complicated due to alloimmunization. Maternal sensibilization had likely occurred in the second pregnancy, when a placental abruption caused severe anemia requiring maternal erythrocyte transfusion. Previous sibling (from the 3rd and 4th gestations) also had alloimmunization with anti-c antibodies, requiring aggressive phototherapy and erythropoietin treatment.At 37 weeks, the antibody titres were significantly elevated, corresponding to a markedly increased concentration of circulating maternal antibodies. The ultrasounds performed during the pregnancy showed no signs suggestive of fetal anemia. The newborn was admitted at birth to the neonatal intensive care unit for treatment with intensive phototherapy. Cord blood bilirubin was 3.7 mg/dL and direct antiglobulin test was positive with a titter of 10/12. At the 3rd hour of life total serum bilirubin was 5.2 mg/dl, hematocrit 49.4% and reticulocyte count 353600/uL (8%).The newborn was treated with intensive unidirectional phototherapy, followed by conventional phototherapy,continuous in the first 48 hours and intermitente until the 6th day of life. Hemoglobin nadir was at 5th week, 7.0 g/dl and did not require erythrocyte transfusion or erythropoietin. The transfontanellar ultrasound showed no abnormalities. Currently, the infant is medicated with folic acid and vitamin D, and continues her follow-up at the neonatology clinic. It´s also being followed at the otorhinolaryngology for serial hearing screenings, although the otoacoustic emissions and auditory evoked potentials during hospitalization were normal.Learning Points/ Discussion: Erythrocyte alloimunization can cause clinically significant hemolytic disease of the fetus and newborn. In the present case, the need for a possible exchange transfusion was anticipated before delivery, and timely and aggressive phototherapy was provided, highlighting the complexity of management. Anti-c alloimmunization may also affect subsequent pregnancies, which makes careful management of both the pregnancy and fetus indispensable. For this reason, close monitoring (optional, with serial antibody titration and ultrasound surveillance) is essential to ensure timely detection and intervention in case of fetal involvement.
