[Non-invasive fetal RhD typing and RhD negative pregnant women--preliminary observations].

OBJECTIVES

For a follow up of a pregnancy in a RhD neg women it is crucial to learn whether her fetus is RhD pos or neg.

AIM

Detection of fetal RHD gene in the plasma of RhD neg mother in various periods of pregnancy and a comparison with RhD of a newborn. 45 plasma samples from various periods of pregnancy from 28 RhD neg women.

MATERIAL AND METHODS

Examination of: RHD (exon 7 and 10), SRY, GSTM1 and ACE using real-time PCR.

RESULTS

Fetal RHD was detected in all 23 mothers with RhD pos child; in one of them, in the 12th week of gestation, RHD was detected only using primers for exon 7, however in the 21st--the presence of both RHD exons was confirmed. Five mothers delivered RhD neg newborns--both RHD exons were not detected. In all 5 cases other fetal genes were examined to be certain that the fetal DNA was analysed. In all 3 mothers who delivered RhD neg boys, the SRY was detected. Among 2 mothers who delivered RhD neg girls, the presence of fetal DNA was confirmed in one, by GSTM1 detection.

CONCLUSIONS

1. Real-time PCR is an appropriate, non-invasive method for fetal RhD examination. 2) Two RHD exons should be examined. 3) Control genes should be investigated and found to be sure that negative result of the RHD was not false negative due to the lack of fetal DNA; SRY is an appropriate control for boys, while for girls further investigations are needed, which are in progress.