A study recently published in Obstetrics and Gynecology Clinics of North America highlights the variation in global guidelines for the use of Rhesus D (RhD) testing and administration of RhD immune globulin (RhIGRho(D) immune globulin A preventive treatment that helps prevent Rh-negative mothers from developing antibodies that may harm the fetus.) during bleeding events in the first trimester. RhD is one of several antigensAntibody A protein made by the immune system that recognizes and attacks foreign substances, such as bacteria, or in HDFN, fetal red blood cells carrying incompatible antigens. implicated in hemolytic disease of the fetus and newborn (HDFN).
If pregnant patients who are negative for the RhRh factor A protein or antigen found on red blood cells. When an Rh-negative mother carries an Rh-positive fetus, her immune system may make antibodies that attack the fetus' red blood cells. antigen are exposed to fetal Rh+ antigens during a bleeding event, an immune response could be triggered that may lead to HDFN in the current or subsequent pregnancies. While the delivery of RhIG to RhD- pregnant individuals during the third trimester is generally supported, some organizations are beginning to recommend against universal RhIG prophylaxis to RhD- patients experiencing bleeding events in the first trimester.
The study revealed that there is limited population-level data suggesting the necessity of RhIG administration during the first trimester in cases of pregnancy loss. “Compelling but indirect clinical data suggests that RhD testing and RhIg prophylaxis are
unnecessary in the first trimester, as the risk of sensitizationSensitization The process by which a mother’s immune system becomes “primed” to recognize and attack fetal red blood cells carrying incompatible antigens. following any bleeding
event at less than 12 weeks likely approaches zero,” the authors added.
The investigators also highlighted the importance of assessing shortages, cost, and access to care when considering RhIg prophylaxis. Overuse of RhIg in high-income countries is not only costly but also detracts resources from areas in which they are needed, they explained.
Read more about HDFN testing and diagnosis
Additionally, several novel treatments for HDFN, such as nipocalimab, have emerged in recent years. These may further reduce the need for first trimester RhIG administration.
The researchers also discussed several national and international guidelines for assessing RhD seropositivity and administering RhIG. They found wide variations in recommendations, emphasizing the need for further research to better understand the utility of RhD testing and prophylaxis during early pregnancy.
“With more data we will be able to determine unified guidelines that offer clarity to clinicians,” the authors wrote. “In turn, they can empower their patients to make informed, evidence-based decisions about RhD testing and RhIg prophylaxis.”
Sign up here to get the latest news, perspectives, and information about HDFN sent directly to your inbox. Registration is free and only takes a minute.
