Rh Immune Globulin (RhoGAM)
| Drug | Class | Route | Key Timing |
|---|---|---|---|
| Rho(D) immune globulin (RhoGAM, MicRhoGAM, WinRho SDF) | Immunoglobulin | IM or IV | 28 weeks antepartum; within 72 hours postpartum |
Clinical Significance
NCLEX Pattern
Rh immune globulin questions focus on: (1) WHO gets it — Rh-negative mother with Rh-positive or unknown-status fetus; (2) WHEN — 28 weeks AND within 72 hours of any sensitizing event; (3) antibody screen is FALSE POSITIVE for 12 weeks after administration.
Pathophysiology: Rh Isoimmunization
When an Rh-negative pregnant person is exposed to Rh-positive fetal blood, the immune system mounts an antibody response — Rh isoimmunization:
Sensitization Sequence:
- First exposure (initial pregnancy or sensitizing event): Rh-positive fetal blood enters Rh-negative maternal circulation → immune system produces IgM anti-Rh antibodies → IgM does NOT cross the placenta; fetus is typically unaffected
- Subsequent exposure (later pregnancy): Memory B cells rapidly produce IgG anti-Rh antibodies → IgG DOES cross the placenta → attacks fetal Rh-positive RBCs → hemolysis → hemolytic disease of the newborn (HDN)
Consequences of Untreated Rh Isoimmunization:
- Severe fetal hemolytic anemia
- Hydrops fetalis (accumulation of fluid in fetal tissues)
- Intrauterine fetal demise
Drug Profile: Rho(D) Immune Globulin
Mechanism: Passively administered anti-Rh antibodies bind and destroy any fetal Rh-positive red blood cells that entered maternal circulation → prevents the maternal immune system from mounting its own active antibody response → no sensitization occurs.
Dosing:
| Indication | Dose | Route |
|---|---|---|
| Antepartum (28 weeks) | 300 mcg | IM or IV |
| First trimester abortion or ectopic pregnancy | 50 mcg (MicRhoGAM) | IM |
| After 13 weeks: abortion, invasive procedure, trauma, delivery | 300 mcg | IM or IV |
| Postpartum (within 72 hours of delivery) | 300 mcg | IM or IV |
72-Hour Window
Rh immune globulin must be administered within 72 hours of delivery or any sensitizing event to be effective. After 72 hours, the maternal immune response may already be underway and cannot be fully suppressed.
Indications (any Rh-negative person with an Rh-positive or unknown-status fetus):
- Routine antepartum prophylaxis at 28 weeks’ gestation
- Spontaneous abortion, threatened abortion, or ectopic pregnancy
- Induced abortion or termination
- Any invasive prenatal procedure (amniocentesis, chorionic villus sampling)
- Significant abdominal trauma during pregnancy
- External cephalic version (ECV)
- Delivery of Rh-positive newborn (within 72 hours)
- Placenta previa or abruptio placentae with bleeding
Contraindications: Known hypersensitivity or anaphylaxis to any component of the drug; existing Rh sensitization (antibodies already present — drug cannot undo established immunity).
Side Effects and Adverse Reactions:
- Common: Pain and redness at IM injection site; mild fever
- Rare: Anaphylaxis (have emergency equipment available); hemolytic reactions
Antibody Screen Interpretation
False Positive Antibody Screen
Rho(D) immune globulin causes the antibody screen (indirect Coombs test) to be falsely positive for up to 12 weeks after administration. Document the date of administration in the chart to prevent misinterpretation as true Rh sensitization.
Nursing Administration
Before Administration:
- Confirm patient’s blood type and Rh status (Rh-negative required)
- Confirm fetal/newborn blood type if available (Rh-positive = confirmed indication; unknown = administer prophylactically)
- Verify antibody screen is negative (sensitization has NOT yet occurred)
- Check for drug allergies or prior reactions to immune globulin products
Administration:
- IM injection: Deltoid or gluteal muscle; do NOT mix with other IV fluids or medications
- IV: Administer slowly; monitor for infusion reactions
- Document lot number, dose, route, site, and date/time
After Administration:
- Instruct patient to carry RhoGAM identification card in wallet
- Advise to notify all future healthcare providers of Rh-negative status
- Inform patient that the 28-week dose is routine — does NOT indicate a problem with the pregnancy
Patient Education:
- Report immediately: shortness of breath, headache, muscle pain, signs of allergic reaction
- Explain the purpose: “This medication prevents your immune system from developing reactions that could harm a future baby’s red blood cells”
- Emphasize: RhoGAM must be given after EVERY pregnancy, miscarriage, or bleeding event
Related Concepts
- conditions-limited-to-pregnancy — Rh isoimmunization as a pregnancy-specific condition
- pregnancy-loss — Rh-negative patients require RhoGAM after any pregnancy loss
- care-in-the-first-trimester-of-pregnancy — Blood type/Rh screening on first prenatal visit
- care-in-the-third-trimester-of-pregnancy — Routine 28-week antepartum prophylaxis
- hypersensitivity-types-and-anaphylaxis-response — Rare anaphylaxis risk with immune globulin
Self-Check
- An Rh-negative patient delivers an Rh-positive newborn at 4 AM. The nurse notes the delivery was 78 hours ago. Should RhoGAM be administered? Why or why not?
- An Rh-negative patient had an indirect Coombs (antibody screen) drawn 6 weeks after receiving Rho(D) immune globulin at 28 weeks. The result is positive. The charge nurse is alarmed. What explanation should the nurse provide?
- An Rh-negative patient at 10 weeks’ gestation experiences a spontaneous abortion. What dose of Rh immune globulin is appropriate, and what is the brand name for this formulation?