Circulating cell‐free DNA levels increase variably following chorionic villus sampling

Abstract

Objective Cell-free fetal DNA (cffDNA) in maternal plasma results from degradation of fetal and/or placental cells. Our objective was to determine if chorionic villus sampling (CVS) causes increased release of fetal and/or maternal DNA. Methods Fifty-two pregnant women were recruited prior to CVS, performed for clinical indications, at 10 5/7 to 13 2/7 weeks. Maternal blood was collected before and within 15 minutes after CVS. cffDNA was extracted from plasma. Real-time polymerase chain reaction (PCR) amplification of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and the Y chromosome sequence DYS1 were used as measures of total and fetal DNA, respectively. All samples were analyzed in triplicate without knowledge of fetal gender. Results Sensitivity of DYS1 detection in male fetuses was 100% (n=30); specificity in female fetuses was 100% (n=22). While a majority of women had >50% post-procedure increases in both fetal and total DNA, some showed post-procedure decreases. However, overall median proportional increases were not statistically significant. Gestational age (GA), placental location, and individual CVS operator did not correlate with changes in DNA levels. Conclusions While there were no statistically significant overall changes in DNA levels after CVS, as-yet undiscovered variables may influence the extent of post-procedure release of cell-free DNA in the circulation of pregnant women.

Non-invasive prenatal diagnostic test accuracy for fetal sex using cell-free DNA a review and meta-analysis

“…Fifty studies were located in Europe [3,7,8,20,25-27,29-32,35,37-40,42,46-48,50,52,53,57,59-81,94,98,103], 26 from Asia [4,9,23,24,28,34,36,44,54-56,58,82-86,88,89,91-93,96,100-102], eight from North America [13,21,22,43,51,87,97,99], two from multiple locations [49,90] and a further four from around the rest of the world [33,41,45,95]. Gestational ranges for the pregnant women varied across the studies, as did the amount of blood taken and the volume actually used for extracting DNA (see Additional file 2: Table S1).…”

“…Real-time quantitative (q) PCR was the most commonly applied detection technique (n = 61), with nested PCR used in 15 studies [25,28,34,45,56,58,62,72,76,85,93,96,100,102,103], standard PCR used in a further eleven studies [3,20,23,24,29,31,65,84,88,95,101], and other methods used in three studies [47,55,82]. SRY alone was used for fetal sex determination in 49 studies, DYS14 alone in 17 studies [3,9,13,23,28,33,41,42,46,49,57,58,65,68,76,100], both SRY and DYS14 in a further five studies [7,27,32,40,69], with 19 other studies [20,21,24,31,43,51,62,63,72,77,82,84,87,88,91,94,97,101,102] using different markers including amelogenin (n = 6) [31,62,63,72,91,102] or a combination of markers. Only four studies specifically recorded inconclusive results or failed tests [7,27,29,52].…”

Single-Nucleotide Polymorphism–Based Noninvasive Prenatal Screening in a High-Risk and Low-Risk Cohort

“…Of these, 401 were prospective high-risk blood samples from women planning to undergo an invasive procedure (amniocentesis or CVS) who subsequently had a confirmatory invasive procedure (398, 60 aneuploid) or who subsequently miscarried and had confirmatory products-of-conception testing (3, 1 aneuploid); 71 (63 aneuploid) were blood samples drawn ≥4 days after an invasive diagnostic procedure; and 71 were blood samples from women with advanced maternal age (≥35) with either follow-up confirmatory sampling at birth (24, none aneuploid) or via confirmatory products-of-conception testing after elective termination (47, 2 aneuploid). Studies have indicated that fetal fractions increase immediately after invasive procedure (26, 27), raising the concern that feto-maternal transfusion could bias results. Preliminary analysis supports that there was no significant increase in fetal fraction at 1 day or 7 days post-invasive procedure (not shown); post-procedure aneuploid samples in this cohort were all drawn at least four days after invasive procedure, reducing the likelihood of procedure-related bias.…”

Isolation and analysis of cell-free fetal DNA from maternal peripheral blood in Chinese women

“…Currently, invasive methods of sampling fetal material include amniocentesis (Fu et al, 2001;Cignini et al, 2012;Simões et al, 2013), chorionic villus sampling (Vora et al, 2010;Colah et al, 2011), and umbilical cord blood sampling (Fu et al, 2000;Deka et al, 2012). Noninvasive prenatal diagnosis (NIPD) is capable of detecting the genetic material of the fetus through the isolation of cell-free fetal DNA (cffDNA) from maternal peripheral blood, plasma, or serum.…”