Introduction: The analysis of free fetal DNA in maternal plasma allows the assessment of fetal genetic material avoiding the necessity of invasive procedures during pregnancy.
Objective: To evaluate the feasibility and the diagnostic performance of fetal sex and fetal RhD detection through the analysis of free fetal DNA in maternal plasma using standard reagents in molecular biology.
Material and methods: A hundred and nine blood samples of pregnant women were obtained. Amplification by real time PCR a sequence from the RhD gene in Rh negative patients and a Y-chromosome sequence, for the diagnosis of fetal Rh and sex respectively, were performed. Results were compared with neonatal outcomes.
Results: From the 109 samples, 26 are still ongoing, 4 ended in spontaneous abortions and in 3 were lost to follow up. From the remaining 76 samples with neonatal result, the determination of fetal Rh from the RhD gene was performed in 65 Rh negative women, whereas in 66 samples the fetal sex analysis was evaluated. Overall, 15 samples had not conclusive results and were excluded from the study. The predictive values for RhD positive and negative were 85% and 90%, respectively, while the prediction for male sex was 94.3% and for female sex 95%.
Conclusion: The non invasive determination of fetal RhD and sex in maternal plasma using standard reagents in molecular biology was feasible in the majority of the samples, with a diagnostic performance similar to the reported in the literature.