Clearance of free fetal DNA after delivery of fetuses carrying chromosomal aneuploidies / 中华医学遗传学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To explore the rules for free fetal DNA clearance after delivery of fetuses carrying chromosomal aneuploidies.</p><p><b>METHODS</b>For 10 women carrying 18-to-25-gestation-week singletons confirmed to have chromosomal abnormalities by amniotic karyotyping, 5 mL of peripheral venous blood was drawn respectively before and 15 minutes, 30 minutes, 60 minutes, 120 minutes, 3 hours, 6 hours, 9 hours, 12 hours, 24 hours, 48 hours and 72 hours after their elective termination of pregnancies. Free fetal DNA was isolated from the plasma and subjected to high throughput sequencing.</p><p><b>RESULTS</b>Statistical analysis of the sequence information showed that the free DNA of fetuses with trisomy 21 or 18 was rapidly cleared after delivery. The average half-life was approximately 1.24 hours within the first 2 hours after delivery. It was then slowly cleared between 6 and 72 hours, with an average half-life of 11.70 hours. No fetal DNA was detectable 72 hours after delivery.</p><p><b>CONCLUSION</b>Free fetal DNA rapidly decreases after delivery and will completely disappear by 72 hours. Above results may provide a basis for clinical application of the non-invasive detection of chromosomal aneuploidies during prenatal diagnosis.</p>