The supply of anti-D immunoglobulin, a prophylactic cornerstone of maternal care, has come under growing strain worldwide. The European Medicines Agency (EMA) recently issued recommendations to strengthen supply and ensure its rational use across Europe.¹ In parallel, the British Society for Haematology (BSH) has updated its guidelines on red cell antibody management in pregnancy, reinforcing the role of fetal RHD genotyping to guide targeted prophylaxis.² The UK has already implemented fetal RHD testing in national programs, showing that it is both practical and effective in reducing unnecessary use of anti-D prophylaxis. Last year, in the United States, the American College of Obstetricians and Gynecologists (ACOG) issued advisories in response to shortages of Rh immune globulin (RhIg or Rhogam).³ These developments reflect a growing international consensus that more precise strategies are needed to safeguard maternal-fetal health while conserving the limited supply available.
The clinical stakes
RhD incompatibility between an RhD-negative pregnant woman and her fetus remains a cause of hemolytic disease of the fetus and newborn (HDFN). Prophylaxis with anti-D immunoglobulin has reduced the incidence of maternal sensitization to only 0.2–0.4 percent in countries with established prevention programs.⁴ However, studies show that up to 40 percent of RhD-negative women carry an RhD-negative fetus, meaning prophylaxis is often administered unnecessarily.⁴ This exposes patients to a blood-derived product without clinical benefit and consumes a limited resource.
Evidence for RHD testing
The foundation for clinical use of noninvasive fetal RHD genotyping was laid in a handful of European countries including Sweden, where more than ten years of experience demonstrated that a single-exon approach is both accurate and practical for routine care.⁵
Building on this foundation, a prospective validation in 261 pregnancies confirmed the robustness of the Devyser RHD assay, with greater than 99 percent accuracy even in the first trimester and consistent performance across fresh and frozen samples.⁶ Most recently, a 31-month follow-up covering nearly 7,000 pregnancies in western Sweden demonstrated the reliability of large-scale single-exon testing. The assay achieved 99.95 percent sensitivity, 100 percent specificity, and 99.97 percent accuracy, with only 0.6 percent of cases inconclusive due to maternal RHD variants, most often in women of non-European ancestry. Based on these results, serological typing of newborns from RhD-negative mothers was discontinued in Stockholm in 20205, and in Gothenburg in 2023, as molecular testing alone was deemed sufficient for clinical safety. ⁷
Independent evaluations also confirm the assay’s performance internationally. A head-to-head comparison of three commercial kits, including Devyser RHD*, found strong concordance with newborn serology in Canada. The few discrepancies observed were linked to rare RHD variants, and importantly, occurred with both single- and multi-exon assays. In all such cases, the inconclusive results underlying the observed discrepancies would result in prophylaxis administration, ensuring no loss of clinical protection. ⁸
This data confirms that the Devyser RHD assay is accurate, reproducible, and firmly established in real-world maternal care. Its use for over ten years in Sweden highlights its role in protecting mothers and newborns while conserving limited prophylactic resources.
A global challenge
The recent actions of the EMA, ACOG, and BSH all point in the same direction: relying solely on widespread administration of a biologically sourced product is no longer sustainable. By integrating fetal RHD testing into routine prenatal care, healthcare systems can ensure that every dose of anti-D immunoglobulin is used where it is truly needed. This approach conserves supply while reducing unnecessary patient exposure to a human-derived product.
Devyser’s role
At Devyser, we are committed to equipping laboratories with tools that simplify complex testing workflows. Devyser RHD is IVDR-certified per European, Australian, and Canadian regulatory standards, offering a validated and efficient non-invasive prenatal RHD testing solution. Enabling targeted prophylaxis helps preserve limited prophylaxis supply, protects mothers and babies, and reduces waste while supporting more resilient healthcare systems.
The shortage of anti-D immunoglobulin is a serious challenge, but it also presents an opportunity to modernize maternal care. The evidence shows that fetal RHD testing is scientifically robust and essential to safeguarding maternal and newborn health in a world of constrained resources.
References
*Disclaimer: Devyser products are distributed worldwide. Not all intended uses and applications mentioned here are available in every country. Please consult your local sales representative for details.