Rh Incompatibility in Pregnancy

• Rh incompatibility occurs during pregnancy when an Rh-negative mother carries an Rh-positive fetus.
• The guide covers causes, risks, symptoms, and treatment options.

Rh Factor

• The D antigen, or Rh factor, is an inherited protein on red blood cells.
• If blood has the protein it's Rh-positive (+), if it lacks the protein it's Rh-negative (-).
• Rh factor is important when an Rh-negative mother is pregnant with an Rh-positive baby

Sensitization

• Sensitization happens when an Rh-negative mother is exposed to Rh-positive fetal blood.
• The exposure can occur during delivery, miscarriage, ectopic pregnancy, or abdominal trauma.
• The mother's immune system recognizes the Rh antigen as foreign, producing Rh antibodies.
• These antibodies can attack Rh-positive red blood cells in subsequent pregnancies, leading to complications

Risk Factors and Maternal Sensitization

• Prior Rh-positive exposure from previous pregnancies, miscarriages, abortions, or blood transfusions can cause sensitization.
• If the fetus inherits the Rh-positive gene from the father, the mother is at risk of sensitization.
• Amniocentesis, chorionic villus sampling, or trauma during pregnancy can expose the mother to fetal blood triggering maternal sensitization.

Early Detection and Prenatal Screening Methods

• The first prenatal visit includes determining the mother's Rh factor.
• Existing Rh antibodies are screened using an Indirect Coombs test.
• Women at risk of Rh incompatibility are identified early as a result.
• Rh-negative mothers undergo regular antibody screening around 28 weeks.
• Rh immune globulin (RhIG) is administered if no antibodies are present.
• RhIG prevents sensitization if fetal blood enters the maternal circulation.

Symptoms and Clinical Manifestations Before Delivery

• Possible early symptoms include fatigue, shortness of breath, and pallor (pale skin).
• Fetal red blood cells cross into the maternal circulation.
• The maternal immune system recognizes fetal Rh-positive red blood cells as foreign.
• Fetal anemia develops, leading to increased cardiac output.
• Polyhydramnios (excessive amniotic fluid) occurs as a consequence.
• Increased MCA Doppler velocities on ultrasound indicate fetal anemia.
• In severe cases, fetal hydrops may occur, characterized by ascites, pleural effusion, and skin edema.
• Fetal jaundice may be observed due to increased bilirubin levels from red blood cell destruction.

Postnatal Symptoms in Affected Newborns

• Jaundice (yellowing of the skin and whites of the eyes) develops due to increased bilirubin levels.
• Anemia occurs because of low red blood cell count.
• Fatigue, pallor, and shortness of breath can result.
• Organs like the spleen and liver becomes enlarged in an attempt to compensate for the destruction of red blood cells.
• Hypotonia, low muscle tone and lethargy

Potential Complications

• Severe anemia and organ damage can lead to fetal death in the womb.
• Fluid accumulation from hydrops fetalis can cause heart failure, lung problems, and potentially death.
• Swelling or fluid buildup of the baby also results.
• Kernicterus, a brain damage due to high levels of bilirubin

Treatment Approaches

• RhoGAM is an intramuscular injection of Rho(D) immune globulin.
• It's given to Rh-negative mothers at 28 weeks of gestation and within 72 hours after delivery.
• It's also given after any potential sensitizing event like miscarriage or amniocentesis.
• RhoGAM prevents the maternal immune system from producing antibodies against Rh-positive fetal red blood cells.
• Exchange blood transfusions are administered to newborns with severe Rh incompatibility.
• The procedure gradually removes the infant's Rh-positive blood and replaces it with Rh-negative donor blood.
• It effectively reduces bilirubin levels and anemia, while preventing further antibody-mediated red blood cell destruction.
• Intensive phototherapy utilizes high-intensity blue light to isomerize unconjugated bilirubin into a water-soluble form.
• The water soluble form can be excreted in the urine and stool, reducing the risk of kernicterus in newborns.
• The infant's eyes are protected with specialized eye coverings during treatment.

This guide explains Rh incompatibility during pregnancy, when an Rh-negative mother carries an Rh-positive fetus. It covers Rh factor, sensitization, risk factors, and maternal sensitization. Learn about the causes, risks, symptoms, and treatment options.