February 25, 2011 by dailybolusoflr
All Rh-negative patients who present with bleeding should be treated with Rhogam.
Pathophysiology of isommunization:
· Fetal RBC’s cross into maternal circulation and antibodies develop against the fetal antigens (when the fetus is Rh+).
· Subsequent pregnancies are at risk. The maternal immune system is activated antibodies are created in large quantities against the fetal antigens expressed.
· IgA antibodies cross the placenta and attack fetal RBCs leading to hemolytic anemia, jaundice and/or high output cardiac failure (hydrops fetalis).
-For patients with vaginal bleeding during pregnancy (evidence for actual SAB, recommended but without evidence for threatened Ab).
-For patients with abdominal trauma, even with apparent minor or no injury.
· For gestations under 20 weeks, a dose of 50 ug is usually considered adequate.
(Note: for patients with massive hemorrhage I would likely give the full dose. 50 ug dose protects against 2.5 ml of Rh + RBC’s, while the full 300 ug dose protects against 15 ml of RBC’s or 30 ml of Rh + blood )
· If the dates are unclear, a full dose of 300 ug should be given.
· If the patient has follow up and wishes to be discharged before administration of Rhogam (not generally recommended for ED practice) patients MUST receive Rhogam within 72 hours of the onset of bleeding.
· If the patient presents with repeated episodes of bleeding before 20 weeks gestation, repeat doses of Rhogam are not needed.
Guidelines from ACOG
Linda Regan, MD FACEP
Program Director, Emergency Medicine Residency
Johns Hopkins Medical Institutions