Early fetal gender determination using real-time PCR analysis of cell-free fetal DNA during 6th-10th weeks of gestation.

Nowadays, new advances in the use of cell free fetal DNA (cffDNA) in maternal plasma of pregnant women has provided the possibility of applying cffDNA in prenatal diagnosis as a non-invasive method. In contrary to the risks of invasive methods that affect both mother and fetus, applying cffDNA is proven to be highly effective with lower risk. One of the applications of prenatal diagnosis is fetal gender determination, which is important in fetuses at risk of sex-linked genetic diseases. In such cases by obtaining the basic information of the gender, necessary time management can be taken in therapeutic to significantly reduce the necessity of applying the invasive methods. Therefore in this study, the probability of detecting sequences on the human Y-chromosome in pregnant women has been evaluated to identify the gender of fetuses. Peripheral blood samples were obtained from 80 pregnant women with gestational age between 6th to 10th weeks and the fetal DNA was extracted from the plasma. Identification of SRY, DYS14 & DAZ sequences, which are not presentin the maternal genome, was performed using Real-Time PCR. All the obtained results were compared with the actual gender of the newborns to calculate the test accuracy. Considerable 97.3% sensitivity and 97.3% specificity were obtained in fetal gender determination which is significant in the first trimester of pregnancy. Only in one case, false positive result was obtained. Using non-invasive method of cffDNAs in the shortest time possible, as well as avoiding invasive tests for early determination of fetal gender, provides the opportunity of deciding and employing early treatment for fetuses at risk of genetic diseases.