Noninvasive Prenatal Diagnosis: Using Fetal Cells From Maternal Blood

Fetal cells can be recovered from maternal blood, suggesting that noninvasive prenatal diagnosis is possible. However, recovery and analysis of fetal cells from maternal blood is complex and sensitivity is low because of the rarity of these cells in the maternal circulation. This study was designed to develop a noninvasive, safe, relatively inexpensive, and accurate technique for the prenatal diagnosis of genetic disorders in the first trimester. The study included a systematic evaluation of variables involved in separating and enriching fetal cells isolated from maternal blood through fluorescence activated cell sorting (FACS) and magnetic activated cell sorting (MACS) followed by fluorescent in situ hybridization (FISH) with chromosome-specific DNA probes. The results of these tests were compared to those obtained from amniocentesis or chorionic villus sampling (CVS) on the same women. No clinical decision was made based on the results of the experimental diagnostic/screening technique. Even if the biological risks associated with reproductive genetic technologies are reduced, it is possible that other risks (or benefits) are associated with the procedures. Some of these factors may be: increased or diminished maternal anxiety, increased adjustment or maladaption to the pregnancy, increased feelings of coercion to undertake the procedure, and increased or decreased comfort with reproductive decision-making. The study also assessed whether there were any nonbiological or psychological effects on the women undergoing prenatal diagnostic testing. After the first five years of the study, preliminary analysis of the data showed that the sensitivity of aneuploidy detection using fetal cell analysis from maternal blood is comparable to single marker prenatal serum screening, but technological advances are needed before fetal cell analysis has clinical application as part of a multiple maker method for noninvasive prenatal screening. Target cell recovery and fetal cell detection were better using MACS than with FACS. The detection rate of finding at least one aneuploid cell in cases of fetal aneuploidy was 74.4%.