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Last reviewed: 16 Mar 2025
Last updated: 11 Apr 2025

Summary

Definition

History and exam

Key diagnostic factors

  • presence of risk 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

Diagnostic tests

1st tests to order

  • maternal blood type
  • maternal serum Rh antibody screen

Tests 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

Treatment algorithm

Contributors

Authors

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

CA

Disclosures

ADH declares that he has no competing interests.

Acknowledgements

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

Disclosures

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

Glasgow

UK

Disclosures

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

Bingley

Bradford

UK

Disclosures

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

Houston

TX

Disclosures

KJM declares that he has no competing interests.

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