Gender determination by isolation of cell-free fetal DNA from the maternal circulation

Objectives: Early identification of fetal gender is important in management of X-linked and other metabolic disorders. Since ultrasound may not predict gender accurately during the first trimester, noninvasive fetal gender determination using deoxyribonucleic acid (DNA) amplification has been proposed. The aim of this study is to evaluate the feasibility of noninvasive prenatal gender determination by examining cell-free fetal DNA (cffDNA) from maternal plasma. Materials and methods: Blood samples were collected from 49 pregnant women of gestational ages ranging from 12 to 41 weeks. Deoxyribonucleic acid was extracted from maternal plasma using a QIAamp DNA Blood Mini Kit. Real-time quantitative polymerase chain reaction (PCR) was performed to amplify the male specific DNA marker sex-determining region Y (SRY). Results: From a total of 49 subjects, fetal gender was correctly determined in 13 out of 14 male fetuses and 32 out of 35 female fetuses, giving an overall accuracy of 92%. The sensitivity and specificity of the test to detect male fetuses was 93 and 91% respectively. There were three false-positive cases and one false-negative case. Conclusion: Identification of fetal gender from maternal plasma using real-time PCR technique is feasible in a developing country, like Pakistan, and appears to be a promising tool for noninvasive prenatal diagnosis.