OBJECTIVE: To examine the possible effects of fetal gender and maternal characteristics on concentration of fetal cell-free DNA (cfDNA). METHODS: Maternal plasma that collected from 2638 singleton pregnancies women were analyzed using non-invasive prenatal testing for aneuploidy by next generation sequence technology. The effects of fetal gender and maternal BMI on fetal cfDNA was measured by Pearson correlation analysis. RESULTS: The proportion of fetal cfDNA was positively correlated with gestational age (regression equation: Y=16.2483+6.8856X, r=0.1660, p<0.0001); and negatively correlated with BMI (Body Mass Index) (regression equation: Y=25.6342-19.0065X, r=-0.2146, p<0.0001); Concentration of female fetal cfDNA (mean fetal cfDNA is 13.07%, p<0.0001) is higher than male fetal cfDNA (mean fetal cfDNA is 8.37%, p<0.0001). CONCLUSIONS: Fetal cfDNA increases stably between 12 and 20 weeks of gestation, and increases in a higher rate after 20 weeks. The maternal BMI is an important factor affecting fetal cfDNA, should be paid enough attention in clinical application.
OBJECTIVE: To examine the possible effects of fetal gender and maternal characteristics on concentration of fetal cell-free DNA (cfDNA). METHODS: Maternal plasma that collected from 2638 singleton pregnancies women were analyzed using non-invasive prenatal testing for aneuploidy by next generation sequence technology. The effects of fetal gender and maternal BMI on fetal cfDNA was measured by Pearson correlation analysis. RESULTS: The proportion of fetal cfDNA was positively correlated with gestational age (regression equation: Y=16.2483+6.8856X, r=0.1660, p<0.0001); and negatively correlated with BMI (Body Mass Index) (regression equation: Y=25.6342-19.0065X, r=-0.2146, p<0.0001); Concentration of female fetal cfDNA (mean fetal cfDNA is 13.07%, p<0.0001) is higher than male fetal cfDNA (mean fetal cfDNA is 8.37%, p<0.0001). CONCLUSIONS: Fetal cfDNA increases stably between 12 and 20 weeks of gestation, and increases in a higher rate after 20 weeks. The maternal BMI is an important factor affecting fetal cfDNA, should be paid enough attention in clinical application.