Prenatal determination of fetal RhD type by DNA amplification

Background. An RhD-negative woman whose partner is heterozygous may have preexisting anti-RhD antibodies that may or may not affect a subsequent fetus, depending on whether it is heterozygous. A safe method of determining fetal RhD type early in pregnancy would eliminate the risks to an RhD-negative fetus of fetal-blood sampling or serial amniocenteses