From the FDA Drug Label
HyperRHO S/D Full Dose is recommended for the prevention of Rh hemolytic disease of the newborn by its administration to the Rho(D) negative mother within 72 hours after birth of an Rho(D) positive infant,... If HyperRHO S/D Full Dose is administered antepartum, it is essential that the mother receive another dose of HyperRHO S/D Full Dose after delivery of an Rho(D) positive infant. The patient is Rh negative and has an antibody screen positive, indicating she is already sensitized to the Rh factor. However, according to the label, if HyperRHO S/D Full Dose is administered antepartum, another dose is needed after delivery of an Rh positive infant.
- The patient was given RhoGAM a month ago and 6 months ago, which means she received it antepartum.
- Since the patient is already sensitized, the primary concern is whether she needs another dose after delivery. Given the patient's sensitization status, the label's recommendation for another dose after delivery is based on the assumption that the mother is not already sensitized. However, since the patient has been given RhoGAM antepartum, and considering the label's instruction to administer another dose after delivery if given antepartum, but also taking into account the patient's sensitization status, the patient likely does not need another dose of RhoGAM today after delivery, as the sensitization has already occurred 1.
From the Research
The patient should receive another dose of RhoGAM (Rh immunoglobulin) after delivery, as the standard postpartum dose is 300 micrograms, which should be administered within 72 hours of delivery for maximum effectiveness, according to the most recent guidelines 2. The patient's Rh-negative status and positive antibody screen indicate a need for protection against potential sensitization from any fetal Rh-positive blood cells that may have entered her circulation during delivery.
- Previous doses given during pregnancy (at 28 weeks and 6 months ago) do not eliminate the need for post-delivery prophylaxis, as each dose provides protection for approximately 12 weeks and addresses different potential exposure events.
- The positive antibody screen should be investigated to determine if it represents anti-D antibodies from the previous RhoGAM administration (which is expected and normal) or if it indicates actual Rh sensitization.
- If the patient has already developed anti-D antibodies naturally (true sensitization), RhoGAM would no longer be beneficial, but this distinction requires laboratory confirmation before withholding treatment, as noted in guidelines from the Journal of obstetrics and gynaecology Canada 3.
- The use of Rho(D) immune globulin in Rh-negative pregnant women has become standard of care, and many practicing clinicians follow the dosing recommendations for this essential medication, as described in a case report in Laboratory medicine 2.
- Quantification of fetomaternal hemorrhage is crucial in determining the adequate dose of RhIG, and laboratories should review their procedures and training for calculating RhIG dosage, as highlighted in a study published in Archives of pathology & laboratory medicine 4.