A screening program in Switzerland based on the noninvasive detection of fetal Rh antigen (RhD) in the blood of pregnant women has shown promising results, allowing preventative measures against hemolytic disease of the fetus and newborn (HDFN) only in pregnancies that require it, according to a recently published study in Biomedicines.
Pregnancies in which the mother is RhD negative and the fetus is RhD positive are at high risk of developing HDFN due to the production of maternal anti-RhD antibodies. For decades, the administration of RH immunoglobulin (RHIG) to RhD-negative pregnant women during the third trimester has been routine. This measure, combined with RHIG administration after birth in cases where the newborn is RhD positive, has reduced HDFN risk to 0.5%.
“RHIG is a blood product prepared from plasma of hyperimmunized donors, thereby raising ethical concerns and bearing a potential risk of infectious diseases for the recipients,” the researchers wrote.
Read more about HDFN testing and diagnosis
According to a study conducted by the National Institutes of Health, only 38% of RhD-negative mothers carried RhD-positive fetuses, meaning that in over 60% of cases, RHIG administration was unnecessary. Recent technological advances have allowed laboratories to determine the fetal RDH status with a maternal blood sample.
Researchers in several countries have used this laboratory technique to establish an advanced screening program in which RHIG is only administered to RhD-negative mothers with RhD-positive babies, thus preventing unnecessary treatment. To that end, the screening program in Switzerland included over 7,000 samples, revealing no false negative cases and only one false positive result.
“In summary, we established a robust method for highly sensitive and specific screening of fetal RhD for targeted RHIG prophylaxis,” the authors wrote. “Based on the obtained results, unnecessary administration could be avoided in more than 98% of those pregnancies where prophylaxis would not have been indicated.”
The results of this study are similar to those obtained in separate studies in the Netherlands and Finland, the authors added, which further validate the program’s efficacy.
