When is RhoGAM (Rho(D) immune globulin) administered in a threatened abortion?

From the Guidelines

Rhogam should be administered to Rh-negative women experiencing a threatened abortion at less than 12 weeks of gestation with a recommended dose of 50 mg within 72 hours of the event, as indicated by the most recent guidelines 1. When considering the administration of Rhogam in the context of a threatened abortion, it's crucial to prioritize the prevention of Rh sensitization to minimize the risk of hemolytic disease of the newborn in future pregnancies.

• The dose of 50 mg is specifically recommended for events occurring at less than 12 weeks of gestation, as it is deemed adequate to cover the volume of potential feto-maternal hemorrhage in the first trimester 1.
• If the 50 mg dose is not available, a 300 mg dose of RhIg may be used as an alternative, although the lower dose is preferred to reduce concerns about resource over-utilization 1.
• It's also important to note that if there is a shortage of the typically used brand of RhIg, an equivalent product may be substituted, such as HyperRHO S/D or Rhophylac, if available 1.
• The timing of Rhogam administration is critical, with the recommendation being within 72 hours of the spontaneous or induced abortion, to ensure maximum effectiveness in preventing Rh sensitization 1.

From the FDA Drug Label

HyperRHO S/D Full Dose should be administered within 72 hours to all nonimmunized Rho(D) negative women who have undergone spontaneous or induced abortion, following ruptured tubal pregnancy, amniocentesis or abdominal trauma unless the blood group of the fetus or the father is known to be Rho(D) negative.

The administration of Rho(D) immune globulin should be given to a nonimmunized Rho(D) negative woman within 72 hours of a threatened abortion, unless the blood group of the fetus or the father is known to be Rho(D) negative 2.

• The main goal is to prevent isoimmunization in the Rho(D) negative individual exposed to Rho(D) positive blood.
• If the fetal blood group cannot be determined, one must assume that it is Rho(D) positive, and HyperRHO S/D Full Dose should be administered to the mother 2.

From the Research

Administration of Rhogam in Threatened Abortion

• The administration of Rhogam in threatened abortion is a topic of debate, with varying guidelines and practices among healthcare providers 3, 4, 5.
• According to the Society of Obstetricians and Gynaecologists of Canada, Rhogam should be given to nonsensitized D-negative women after miscarriage or threatened abortion, with a minimum dose of 120 microg before 12 weeks' gestation and 300 microg after 12 weeks' gestation 3.
• However, other studies suggest that the evidence to support the use of Rhogam in first-trimester spontaneous abortions is minimal, and that the practice of administering Rhogam in this scenario is not evidence-based 4, 6.
• A recent study found that induced first-trimester abortion is not a risk factor for Rh sensitization, indicating that Rh testing and treatment may be unnecessary before 12 weeks' gestation 6.
• The Society of Family Planning committee consensus on Rh testing in early pregnancy also suggests that forgoing Rh immunoglobulin administration before 12 weeks gestation is highly unlikely to increase the risk of Rh (D) antibody development 7.

Key Considerations

• The dose and timing of Rhogam administration in threatened abortion vary depending on the gestational age and the presence of fetomaternal hemorrhage 3, 4.
• Healthcare providers should consider the individual patient's risk factors and medical history when deciding whether to administer Rhogam in threatened abortion 5, 6.
• Further research is needed to determine the optimal approach to Rhogam administration in threatened abortion and to inform evidence-based guidelines 4, 6, 7.