Isoimmunization Erythroblastosis Fetalis Hemolytic Disease of the Newborn

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IsoimmunizationErythroblastosis
FetalisHemolytic Disease of the Newborn

• Zeev Weiner
• Director of Ultrasound in Obstetrics and
  Gynecology
• Lutheran Medical Center

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Rh Isoimmunization

• Rh Blood Group System
• Cc
• Dd
• Ee
• 40 other antigens Du, Cw,.

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The D antigen

• In 85 the D antigen is present
• 55 heterozygous
• Sensitization occurs during blood transfusion and
  during pregnancy

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The D antigen

• Isoimmunization is dose dependent
• 0.1 ml is sufficient
• ABO incompatibility confers partial protection!

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Obstetrical risks for Rh isoimmunization

• Abortions (2-5) How early?
• Pregnancy and delivery (1.6)
• Procedures Amniocentesis
• Trauma

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Rh Hemolytic Disease

• Mild Fetal anemia with Hbgt12-13g/dl.
• No sonographic findings.

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Rh Hemolytic Disease

• Moderate Fetal anemia with Hb between 7-12 g/dl
• Possible sonographic findings.

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Rh Hemolytic Disease

• Severe Anemia with Hb lt 7g/dl
• Most of the time there are sonographic findings

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Monitoring the sensitization

• When do we check anti-D titers?
• At the beginning, 28 wks, after birth
• What is a significant titer?
• Above 18-116
• How accurate are the titers?
• ..
• What is the meaning of very low titers and do we
  have to give prophylaxis?
• .

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Follow-up patients with sensitization

• Checking the Rh antigens of the father if
  negative no need to
• follow-up?
• Checking the Rh antigens of the fetus if negative
  definitely no need to follow-up

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Follow-up patients with Rh isoimmunization

• Follow-up can start at 18 weeks gestation
• There are 3 options
• Amniocentesis
• Cordocentesis
• Doppler

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Amniocentesis for patients with Rh isoimmunization

• The Liley or the modified curves.
• Advantage less complicated procedure
• Disadvantage delta OD may not accurately
  correlate with the anemia

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Cordocentesis for patients with Rh isoimmunization

• Blood sampling from the umbilical vein, hepatic
  or portal veins, intracardiac
• Advantage more reliable, immediate option for
  treatment
• Disadvantage higher risk

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Doppler studies for patients with Rh
isoimmunization

• Peak velocity of the middle cerebral artery (why
  not other vessels?)
• Advantage non invasive
• Disadvantage correlation with anemia is still
  questionable

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Treatment of Fetal Anemia

• Indication Hb lt 10-11 g/L (Hctlt30) or fetal
  hydrops
• Technique Intraperitoneal, Intravascular
  (umbilical vein or others), Intracardiac

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Treatment of Fetal Anemia

• Irradiated O- packed red cells (Hct0.85-0.9)
• V (Hct-f - Hct-i)xEFWx120 Hct-d
• Guidelines for repeat transfusion 1 decline per
  day, Hct25

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Treatment of Severe Cases of Rh Isoimmunization

• Early transfusions starting at 16-18 wks
• A weekly high-dose of IVIG between 13-18 wks
• AID

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Time and Mode of Delivery

• 33-34 wks with documented lung maturity
• 34-36 weeks with no need to document lung
  maturity
• No indication for a CS

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Prevention of Rh Isoimmunization

• 300 micrograms of Anti-D Ab
• At 28 wks and within 72 hrs postpartum
• Protect against 15 ml of RBC

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Other Common antibodies Causing Isoimmunization

• Kell
• C
• E