Quantitative detection of cell-free fetal DNA in peripheral blood of pregnant women during early pregnancy

C Liu,Y Qiu

doi:10.12891/ceog4825.2019

Abstract

Objective: This study aimed for the quantitative detection of cell-free fetal DNA (cffDNA) in peripheral plasma of pregnant women, which provides basic data for clinical non-invasive prenatal screening in early pregnancy. Materials and Methods: A total of 243 individuals with gestational age of 5-10+6 weeks were selected for this study, who required abortion. mDNA was extracted from villi, and Y-chromosome specific SRY gene was detected by nested PCR, which was regarded as standard for quantitative detection of accuracy. CffDNA was extracted from peripheral blood and SRY gene’s expression was detected by real-time fluorescent quantitative PCR. Results: Among 243 cases, nested PCR detected 163 individuals with SRY gene positive, and 80 were negative. Out of 163, in 140 cases SRY was detected in cffDNA, but 23 cases with gestational age 5-6+6 weeks were negative. However at 7th week of pregnancy, it was also detected in those 23 cases. The average concentration of cff DNA in 10th week of pregnancy was found significantly higher than in 7th, 8th, and 9th week of pregnancy. Conclusion: Thus, this study indicates the efficiency and reliability of cffDNA in peripheral blood of 7-10th week of gestational period for the detection of early pregnancy.

Highlights

The previous prenatal diagnosis was based on the extraction of fetal DNA through invasive operation, such as chorionic villus sampling, amniocentesis, and cord blood collection, etc., these methods have risks for both pregnant women and the fetus, and generally they require at least 11 weeks of gestational [1-3]
CffDNA can be detected in maternal peripheral blood as early as 5th week of pregnancy, and the amount of cell-free fetal DNA (cffDNA) is increased with the increase of gestational weeks [7-9]
The results showed that 163 samples are positive for SRY gene and 80 samples were negative

Summary

Introduction

The previous prenatal diagnosis was based on the extraction of fetal DNA through invasive operation, such as chorionic villus sampling, amniocentesis, and cord blood collection, etc., these methods have risks for both pregnant women and the fetus, and generally they require at least 11 weeks of gestational [1-3]. The development of molecular diagnostics aided the use of cell-free fetal DNA (cffDNA), which circulates freely in mother’s blood as a non-invasive method for prenatal diagnosis. The real-time quantitative PCR assay based method to measure the concentration of fetal DNA in maternal plasma and serum in early pregnancy (as well as 7th week of pregnancy) was developed two decades ago [4]. The detection of cffDNA can achieve non-invasive prenatal screening, but can advance the detection of gestational age, and abnormal pregnancy as early as possible, reducing the mental and economic burden of pregnant women and their families

Objectives

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Results

Conclusion