Sweeping changes coming regarding fetal RhD genotyping?

A polymerase chain reaction (PCR)-based assay of antenatal maternal serum can determine fetal Rh status in over 99% of cases with 100% accuracy, according to a recently published French study involving 285 pregnant women. Researchers were able to determine fetal RhD status in all but two cases. (In those two cases, the RhD-negative phenotype of the mother was not the result of a complete RHD gene deletion.) No false-positive or false-negative results occurred; all sera from women carrying an RhD-positive fetus had positive results for RHD gene detection, and all sera from women carrying an RhD-negative fetus had negative results.

The authors concluded that such a test could be offered to all RhD-negative pregnant women to avoid unnecessary use of Rh immune globulin. In addition, such an assay could replace amniocentesis as a means for determining whether a fetus is at risk for hemolytic disease.

Gautier E, Benachi A, Giovangrandi Y, et al. Fetal RhD genotyping by maternal serum analysis: a two-year experience. Am J Obstet Gynecol. 2005;192:666-669.