Is it concerning that a patient with Rh (Rhesus) negative blood type did not receive RhoGAM (Rho(D) immune globulin) in her last pregnancy and has a negative antibody screen for the Rh antigen?

From the Guidelines

The patient's situation is concerning but manageable, and she should receive RhoGAM (300 mcg intramuscularly) immediately if she is currently pregnant and less than 28 weeks gestation, followed by another dose at 28 weeks, to prevent Rh sensitization. The patient is Rh negative and did not receive RhoGAM during her previous pregnancy, which puts her at risk for Rh sensitization. However, the negative antibody screen indicates she has not yet developed anti-Rh antibodies, which is good news 1. According to the most recent study, the Society for Maternal-Fetal Medicine recommends RhoGAM administration after spontaneous or induced abortion at less than 12 weeks of gestation, but notes that the evidence may favor administration of RhoGAM, and the decision should be made as part of a shared decision-making process 1.

Key Considerations

• The patient's Rh negative status and lack of RhoGAM administration during her previous pregnancy put her at risk for Rh sensitization 1.
• The negative antibody screen indicates she has not yet developed anti-Rh antibodies, which is good news 1.
• RhoGAM prevents the mother's immune system from recognizing Rh positive fetal cells that may enter her circulation, thereby preventing antibody formation that could cause hemolytic disease in future Rh positive fetuses 1.
• Without RhoGAM, approximately 17% of Rh negative women become sensitized after an Rh incompatible pregnancy, according to a study published in the Annals of Emergency Medicine 1.

Recommendations

• If she is currently pregnant and less than 28 weeks gestation, she should receive RhoGAM (300 mcg intramuscularly) immediately, followed by another dose at 28 weeks.
• If she is beyond 28 weeks, she should receive a dose now and another within 72 hours after delivery.
• If she's not currently pregnant, she should be counseled about the importance of receiving RhoGAM in all future pregnancies at 28 weeks and within 72 hours after delivery.

From the FDA Drug Label

The mother must be Rho(D) negative and must not already be sensitized to the Rho(D) factor. If the father can be determined to be Rho(D) negative, HyperRHO S/D Full Dose need not be given A screening test to detect fetal red blood cells may be helpful in such cases

The patient is Rh negative and has an antibody screen negative for the antigen. Since the patient did not receive Rhogam in her last pregnancy, there is a risk of sensitization to the Rh factor if the baby is Rh positive.

• If the baby is Rh positive, the patient is at risk of developing antibodies against the Rh factor, which can cause complications in future pregnancies.
• If the father is Rh negative, the risk of sensitization is lower, but it is still important to monitor the patient's antibody screen. It is bad that the patient did not receive Rhogam in her last pregnancy, as this increases the risk of sensitization and potential complications in future pregnancies 2, 2.

From the Research

Patient's Rh Negative Status and Antibody Screen Negative for Antigen

• The patient's Rh negative status and antibody screen negative for antigen indicates that they have not developed antibodies against the Rh antigen 3.
• However, the patient did not receive Rhogam in their last pregnancy, which increases the risk of alloimmunization to the D antigen 4.
• Alloimmunization can lead to hemolytic disease of the fetus and newborn (HDFN) in future pregnancies 5.

Risk of Alloimmunization

• The risk of alloimmunization is higher in Rh negative individuals who do not receive Rhogam during pregnancy 6.
• However, the patient's antibody screen is negative, which suggests that they have not developed antibodies against the Rh antigen yet 3.
• It is essential to monitor the patient's antibody screen regularly to detect any changes in their immune status 7.

Management and Recommendations

• The patient should receive Rhogam in future pregnancies to prevent alloimmunization to the D antigen 4.
• Noninvasive fetal RHD genotyping can be used to predict the fetal RhD phenotype and guide the administration of Rhogam 5.
• The patient's healthcare provider should follow established guidelines for the management of Rh negative pregnant women, including regular antibody screening and Rhogam administration as needed 6, 7.