Fetal RhD genotyping by analysis of maternal blood. A case report.

BACKGROUND

Prenatal determination of fetal rhesus D (RhD) status is desirable in pregnancies in sensitized, RhD-negative women to prevent hydropic degeneration of the fetus. Recently, a polymerase chain reaction (PCR) test on amniocytes or chorionic villi has been in use to demonstrate the RhD status of the fetus in sensitized pregnancies. A more advisable, noninvasive approach is to determine the fetal RhD group from fetal cells circulating in maternal blood.

CASE

We report on a prenatal diagnosis where RhD-positive cells could be detected from peripheral blood of a sensitized, RhD-negative mother. The presence of an RhD-positive fetus was confirmed by subsequent amplification of fetal DNA obtained by chorionic villus biopsy.

CONCLUSION

In sensitized pregnancies, the number of fetal cells in maternal blood seems to be high enough to be detected by PCR in every case.