Anti-D Administration After Delivery of Rh-Positive Baby to Rh-Negative Mother
Give anti-D to the mother only (Option A).
Rationale for Maternal Administration
Anti-D immune globulin should be administered to the Rh-negative mother within 72 hours after delivery of an Rh-positive infant to prevent RhD alloimmunization and subsequent hemolytic disease of the fetus and newborn in future pregnancies. 1, 2
The mechanism works by suppressing the maternal immune response to fetal RhD-positive red blood cells that enter maternal circulation during delivery. 1 Without prophylaxis, approximately 13-17% of Rh-negative mothers delivering Rh-positive infants will develop anti-D antibodies, but postpartum RhIg reduces this risk to 1-2%. 1
Why the Baby Does Not Receive Anti-D
The newborn should never receive anti-D immune globulin. 2 The FDA-approved indication specifically states that anti-D is administered to the Rho(D)-negative mother, not the infant. 2 The baby's Rh-positive red blood cells are the target antigen that could trigger maternal sensitization—giving anti-D to the baby serves no protective purpose and is not indicated. 2
Critical Eligibility Criteria
Before administering anti-D to the mother, verify: 2
- The mother must be Rho(D)-negative
- The mother must not already be sensitized (no pre-existing anti-D antibodies)
- The infant must be Rho(D)-positive
- The infant should have a negative direct antiglobulin test (DAT)
Timing Considerations
The 72-hour window is critical for optimal effectiveness. 1, 2 However, if this window is missed, anti-D should still be given as soon as recognized, up to 28 days after delivery, as delayed administration provides some benefit even though protection decreases over time. 1
Dosing for Standard Delivery
The standard dose is 300 μg (1500 IU) administered intramuscularly or intravenously. 1, 2 Both routes are equally effective based on available evidence. 3
When Additional Doses Are Required
If fetomaternal hemorrhage exceeds 15 mL of fetal red blood cells (approximately 30 mL of fetal blood), additional anti-D is required at 10 μg per 0.5 mL of fetal red blood cells. 1, 4 Events with substantial placental trauma—such as placental abruption, abdominal trauma, or complicated deliveries—warrant consideration of quantitative testing for fetomaternal hemorrhage to determine if supplemental dosing is needed. 1, 4
Common Pitfall to Avoid
Do not withhold anti-D if the father's Rh status is unknown or if paternity is uncertain—always assume the infant is Rh-positive unless proven otherwise. 2, 4 The consequences of sensitization (severe HDFN in subsequent pregnancies, need for fetal transfusions, hydrops, stillbirth) far outweigh the minimal risks of anti-D administration. 1