Hemolytic Disease of Newborn (HDN)

[Audio] "Welcome to this overview of Hemolytic Disease of the Newborn, or HDN. This immune-mediated condition occurs when a mother's antibodies attack her baby's red blood cells due to blood type mismatches, like Rh-negative mother with Rh-positive fetus . It affects about 1 in 59 live births overall, though Rh cases are rarer now..

[Audio] In definition, hemolytic disease of the fetus and newborn is a condition where fetal red blood cells are destroyed by maternl antibodies due to blood group incompatibility, primarily involving Rh or ABO blood types..

[Audio] Under the blood group classifications, the most common types of red blood cell antigens are; ABO classification & Rh classification.

[Audio] Individuals have antibodies to antigens that are not on their own red blood cells, which is a defense mechanism against the presence of foreign blood or body parts in their bodies. Majority of the Antibodies for antigen A and B are Immunoglobulin M, but some IgG may be present. The majority of Rh antibodies are of the ImmunoglobulinG type , the only type which can cross the placenta . Antibodies for Rh don't occur naturally; exposure to the Rh-positive blood is essential.

Rh Classification. Presence of the D agglutinogen (DD or Dd) – Rh Positive Absence of the D agglutinogen (dd) - Rh Negative The majority of Rh antibodies are of the IgG type (some IgM). Abs for Rh don’t occur naturally; exposure to the Rh-positive blood is essential IgG is the only antibody class that crosses the placenta through the syncytiotrophoblast layer..

[Audio] "HDN stems from alloimmunization. In Rh HDN, fetal-maternal bleeding during pregnancy exposes the mother to RhD antigen, producing IgG anti-D antibodies. These cross the placenta in subsequent pregnancies, binding fetal RBCs and causing hemolysis. ABO HDN is milder, often in group O mothers with A/B babies, due to natural IgG antibodies..

[image] Hemolytic Disease of the Newborn (HDN) First Fetus During Sensitization MotherS Circulation Rhogam (anti-Rh0(D) antibody) delivery Hemolytic Disease of the Newborn Second Fetus Mother's Circulation • Severe anemia • Hydrops fetalis After birth • Bilirubin accumulation • Kernicterus (irreversible brain damage) • Hepatosplenomegaly • Delayed anemia (weeks post delivery).

[Audio] During fetal life, maternal liver clears bilirubin; post-birth, neonatal jaundice emerges within 24 hours "Severe cases show fetal anemia, hydrops fetalis, or neonatal hyperbilirubinemia risking kernicterus—brain damage from bilirubin deposition . Signs include pallor, hepatosplenomegaly, and rapid jaundice. Diagnosis uses maternal antibody screen, amniocentesis for bilirubin, or Doppler for fetal anemia.

[Audio] "Treatment escalates by severity: phototherapy for mild jaundice, exchange transfusion for moderate, or intrauterine transfusion for fetuses . Survival exceeds 90% with timely intervention, especially early IUT . IVIG reduces hemolysis needs "Prevention transformed HDN: Rh immunoglobulin (RhIg) at 28 weeks and postpartum for Rh-negative mothers halves sensitization to under 0.5% . Universal screening prevents most cases.

[Audio] "Thanks to prophylaxis, HDN deaths dropped dramatically. For updates, see recent reviews.