Genotyping fetal DNA by non-invasive means: extraction from maternal plasma

Background and Objectives Identification of fetal DNA in maternal plasma may allow genetic analysis without the use of invasive techniques. The aim of this study was to extract DNA from maternal plasma, identify fetal material through the presence of SRY or RHD gene sequences and assess the reliability of these results. Materials and Methods A polymerase chain reaction (PCR) method of a commercial kit was used with primers for SRY or exon 10 of the RHD gene sequence. Results Multiple plasma samples were collected from 60 women who were evaluable for either SRY or RHD, or both, fetally derived DNA sequences. Fetal DNA was present in the plasma throughout the pregnancies and for some hours or days after delivery. Conclusion Fetal DNA can be reliably detected in maternal plasma from early in pregnancy and normally is cleared within days of delivery.