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Rh incompatibility

Last reviewed: 1 Nov 2023
Last updated: 16 Feb 2023



History and exam

Key diagnostic factors

  • presence of risk factors
More key diagnostic factors

Risk factors

  • history of an RhD-positive fetus in an RhD-negative mother
  • fetomaternal hemorrhage
  • invasive fetal procedures
  • placental trauma
  • abortion
  • multiparity
  • omission of Rh immunoprophylaxis
  • external cephalic version
  • molar pregnancy
  • ectopic pregnancy
More risk factors

Diagnostic investigations

1st investigations to order

  • maternal blood type
  • maternal serum Rh antibody screen
More 1st investigations to order

Investigations to consider

  • maternal serum antibody titer
  • paternal blood type
  • paternal zygosity
  • fetal ultrasound
  • Doppler velocimetry of fetal middle cerebral artery (peak systolic velocity)
  • fetal blood typing (from amniocentesis or maternal circulation)
  • direct assessment of fetal anemia
  • rosette test
  • Kleihauer-Betke test/flow cytometry
More investigations to consider

Treatment algorithm


unsensitized RhD-negative mother

sensitized RhD-negative mother


neonate with erythroblastosis



Andrew D. Hull, MD, FRCOG, FACOG

Professor of Clinical Obstetrics, Gynecology, and Reproductive Sciences

Director, UC San Diego Maternal-Fetal Care and Genetics

Division of Maternal-Fetal Medicine

Department of Obstetrics, Gynecology, and Reproductive Sciences

University of California San Diego

La Jolla



ADH declares that he has no competing interests.


Dr Andrew D. Hull would like to gratefully acknowledge Dr Karen Fung-Kee-Fung and Dr Felipe Moretti, previous contributors to this topic.


KFKF is an author of a reference cited in this topic. KFKF and FM declare that they have no competing interests.

Peer reviewers

Alan Cameron, MD

Honorary Professor of Medicine

University of Glasgow




AC is an author of several references cited in this topic.

Liakat Ali Parapia, MD, FRCP

Consultant Hematologist

Bradford Teaching Hospitals NHS Trust

Yorkshire Clinic





LAP declares that he has no competing interests.

Kenneth J. Moise, Jr., MD

Professor of Obstetrics and Gynecology

Texas Children's Fetal Center

Baylor College of Medicine/Texas Children's Hospital




KJM declares that he has no competing interests.

  • Rh incompatibility images
  • Differentials

    • Nonimmune fetal hydrops
    • Parvovirus infection
    • Non-RhD hemolytic disease
    More Differentials
  • Guidelines

    • FIGO/ICM guidelines for preventing Rhesus disease: a call to action
    • ACOG practice bulletin no. 192: management of alloimmunization during pregnancy
    More Guidelines
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