5 Things Doctors Don't Tell You About Rh Incompatibility скачать в хорошем качестве

5 Things Doctors Don't Tell You About Rh Incompatibility

Rh Incompatibility Definition Rh incompatibility occurs when: Mother is Rh-negative (Rh–) Fetus is Rh-positive (Rh+) and fetal RBCs enter the maternal circulation, causing the mother to produce anti-Rh (anti-D) antibodies, which can cross the placenta and destroy fetal red blood cells. This leads to Hemolytic Disease of Fetus and Newborn (HDFN). Basics of Rh Blood Group Rh factor (D antigen) Present → Rh positive Absent → Rh negative Genetics: Rh+ is dominant Rh– is recessive Example: Father Rh+, Mother Rh– → baby may be Rh+ Pathophysiology (Mechanism) Step-by-step process 1. First exposure (sensitization) Fetal Rh+ blood enters maternal circulation during: Delivery Abortion Ectopic pregnancy Antepartum hemorrhage Amniocentesis Trauma Placental separation Mother forms: IgM antibodies first → cannot cross placenta Later → IgG antibodies → can cross placenta First baby usually safe. 2. Subsequent pregnancy (immune reaction) If next fetus is Rh+: Maternal IgG anti-D antibodies cross placenta Destroy fetal RBCs Causes hemolysis Results in: Anemia Jaundice Edema Organ enlargement Heart failure Hydrops fetalis Effects on Fetus and Newborn Due to RBC destruction 1. Anemia Reduced oxygen supply Bone marrow hyperactivity 2. Extramedullary hematopoiesis Liver & spleen enlarge 3. Hyperbilirubinemia RBC breakdown → bilirubin ↑ After birth → jaundice 4. Hydrops fetalis (severe) Fluid accumulation: Ascites Pleural effusion Edema Pericardial effusion Can cause: Heart failure Intrauterine death Clinical Features During pregnancy Usually asymptomatic mother May show: Polyhydramnios Fetal anemia Hydrops on ultrasound At birth (baby) Mild Mild jaundice Moderate Anemia Jaundice within 24 hours Hepatosplenomegaly Severe Hydrops fetalis Severe anemia Heart failure Stillbirth Kernicterus (dangerous complication) Bilirubin deposits in brain Leads to: Seizures Mental retardation Deafness Death Investigations Mother Blood tests Blood group & Rh typing Indirect Coombs test (ICT) → Detects maternal antibodies Antibody titer 1:16 → risk to fetus Fetus Ultrasound → hydrops, hepatosplenomegaly Middle cerebral artery Doppler → fetal anemia Amniocentesis → bilirubin levels Cordocentesis → Hb level Newborn Direct Coombs test (DCT) positive Hb ↓ Bilirubin ↑ Reticulocytes ↑ Management A. Prevention (MOST IMPORTANT) Anti-D immunoglobulin (RhIg) Given to Rh– mother: At 28 weeks pregnancy Within 72 hours after delivery of Rh+ baby After: Abortion Ectopic pregnancy Amniocentesis Trauma APH Dose 300 µg IM Action Destroys fetal RBCs before immune response Prevents antibody formation B. During pregnancy (if sensitized) Monitor: Antibody titers Ultrasound Doppler studies If fetal anemia: Intrauterine transfusion Early delivery C. After birth (baby) Treatment: Phototherapy Exchange transfusion Blood transfusion IV immunoglobulin Complications Fetal Severe anemia Hydrops fetalis IUFD Neonatal Jaundice Kernicterus Brain damage Maternal Usually none