Scientific Journal of

  Abstract

 Background and Objectives

 RhD antigen has an important role in causing hemolytic diseases in newborns in testing fetal RhD status by an invasive method such as amniocentesis, it would also harm the fetus and mother. This study tried to detect fetal RhD genotype using free fetal DNA in maternal serum by a noninvasive method using hemi-nested PCR.

 Materials and Methods

 Blood samples were collected from 45 RhD- negative pregnant women whose spouses were Rh-positive the women's serum free DNAs were isolated by Phenol-Chloroform method. The exon 10 of the RhD genes was amplified in two rounds of PCR using special primers. For confirmation of negative results obtained in the second PCR, the fragment of the RhCE gene was amplified using special primers.

 Results

 Follow up and evaluation of the PCR results and relevant serological analysis of cord blood after delivery revealed that in 37 out of 41 cases the RhD had been determined appropriately (95.45%). There were one false-negative and three false-positive cases.

 Conclusions

 This study showed that maternal serum is very suitable for prenatal diagnosis of fetal RhD using noninvasive methods with minimum risk for neonates. In this regard, modern molecular methods with high sensitivity such as hemi-nested PCR and elimination of interfering factors could be applicable in clinical approaches.

 Key words : Pregnancy , Serum, RhD, RhCE, PCR