Evaluation of Different Approaches for Fetal DNA Analysis from Maternal Plasma and Nucleated Blood

One potential noninvasive approach for antenatal diag-nosis is the use of fetal cells in maternal circulation as a source of fetal DNA (1). To date, fetal DNA has been extracted from maternal nucleated blood cells and ampli-fied by nested PCR of Y-chromosome sequences from male fetuses (2, 3). A recent study (4) demonstrated the presence of fetal DNA in maternal plasma. After a single PCR with a high number of cycles, detection of fetal DNA was possible in 24 (80%) of the 30 maternal plasma samples, using 10 mL of boiled plasma (4). When DNA extracted from a similar volume of whole blood was used, only 17 % of the samples gave a Y-positive signal, suggesting an enrichment of fetal DNA in plasma compared with whole blood cells (4). The mechanism responsible for fetal DNA release in materna