RESUMO
Owing to the lack of perfect accuracy and sufficient sample size in previously performed studies on cell-free foetal DNA (cffDNA) for detection of foetal gender through maternal plasma, this study aimed to investigate the efficiency of using two Y-chromosome specific probes in foetal sex determination during first trimester of pregnancy. Five millilitres of whole blood was drawn from 192 pregnant women (10-12 weeks) and was subjected to isolate cffDNA following separation of plasma. TaqMan Real-time PCR was performed on isolated cffDNA using primer pairs and probes specific for SRY, ZFY and ß-globin genes. Co-amplification of ZFY and SRY genes was detected in 103 samples confirmed after the birth. Sensitivity and specificity of the test were calculated to be 100%. Further study on larger sample size is required to confirm the reproducibility of the present test in early and non-invasive determination of foetal sex. IMPACT STATEMENT What is already known on this subject? Foetal gender analysis through maternal plasma has been investigated in some cell-free foetal DNA (cffDNA) analysis. However, the detection rate and method of cffDNA analysis were different among various studies. What do the results of this study add? This study introduced a modified simple probe based real time analysis with perfect detection rate. What are the implications of these findings for clinical practice and/or further research? The proposed method can be used as diagnostic test in all laboratories around the world using real-time PCR to non-invasively determine the foetal gender in the initial weeks of pregnancy following confirmation in larger sample size.