Genotyping to prevent Rh disease: has the time come?

In this review, we analyzed the current literature on noninvasive fetal RHD typing to answer the question whether the administration of RhIg to prevent D-alloimmunization during pregnancy can be safely guided by fetal RHD typing. Recently the first centers that implemented large-scale nationwide fetal RHD typing in the second trimester for targeted RhIg administration have published their studies evaluating the diagnostic accuracy of their screening programs. These data show that fetal RHD typing in a routine setting is, at least in a population of European descent, accurate enough to guide both antenatal and postnatal immunoprophylaxis. Depending on the ethnic background and the organization of pregnancy care the decisions regarding RhIg can be safely and cost-effectively based on fetal RHD typing by a duplex real-time PCR. As a result, the unnecessary administration of 40% of antenatal RhIg can be prevented, and cord blood serology can be omitted.