Can Rho(D) immune globulin (Winrho) be administered at 27 weeks of gestation in an Rh-negative pregnant woman?

From the FDA Drug Label

The administration of Rho(D) Immune Globulin (Human) within 72 hours of a full-term delivery of an Rho(D) positive infant by an Rho(D) negative mother reduces the incidence of Rh isoimmunization from 12%–13% to 1%–2%.(9) The 1%–2% treatment failures are probably due to isoimmunization occurring during the latter part of pregnancy or following delivery. (10) Bowman and Pollock(11) have reported that the incidence of isoimmunization can be further reduced from approximately 1.6% to less than 0. 1% by administering Rho(D) Immune Globulin (Human) in two doses, one antenatal at 28 weeks’ gestation and another following delivery.

Administration at 27 weeks is not explicitly mentioned in the drug label. However, it is mentioned that Rho(D) Immune Globulin (Human) can be administered antenatally at 28 weeks’ gestation. Since 27 weeks is close to the recommended 28 weeks, but not exactly the same, caution should be exercised. The label does not provide direct information to support administration at 27 weeks, but it does suggest that administration at a similar gestational age (28 weeks) can be beneficial in reducing the incidence of isoimmunization 1.

• Key consideration: The drug label does not directly address administration at 27 weeks pregnant.
• Clinical decision: Given the information provided, it is unclear if Winrho can be safely administered at 27 weeks pregnant, as the label specifically mentions 28 weeks. Therefore, no conclusion can be drawn regarding administration at 27 weeks based on the provided drug label information.

From the Research

Yes, Rho(D) immune globulin (WinRho) can and should be administered at 27 weeks of gestation in an Rh-negative pregnant woman. The standard protocol recommends that Rh-negative women who are not already sensitized receive a prophylactic dose of Rho(D) immune globulin at 26-28 weeks of pregnancy, making 27 weeks an appropriate time for administration, as indicated by the most recent guidelines 2. This preventive measure is crucial because it protects against maternal sensitization to the Rh(D) antigen that may occur due to small, clinically undetectable fetomaternal hemorrhages during pregnancy. If the woman becomes sensitized, her immune system would produce antibodies that could cross the placenta in current or future pregnancies and attack the red blood cells of an Rh-positive fetus, potentially causing hemolytic disease of the newborn. Key points to consider include:

• The administration of Rho(D) immune globulin is a well-established practice for preventing RhD alloimmunization in RhD-negative pregnant women 3, 2.
• The medication is administered as an intramuscular injection, typically in the deltoid or gluteal muscle, and is generally well-tolerated with minimal side effects.
• In addition to this routine antenatal administration, Rh-negative women should also receive another dose of Rho(D) immune globulin within 72 hours after delivery if the baby is Rh-positive.
• Recent studies suggest that cell-free DNA tests can be used to predict fetal Rh(D) status and prioritize Rho(D) immune globulin administration, especially in cases of shortage 4. However, the primary consideration should always be the prevention of maternal RhD alloimmunization to ensure the best possible outcomes for both the mother and the fetus, as emphasized in the most recent and highest quality study 2.