title: 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 min 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.
authors.affiliation: Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, Tufts Medical Center, Boston, MA 02111, USA.
authors.forename: Neeta L
authors.initials: NL
authors.lastname: Vora
authors.forename: Kirby L
authors.initials: KL
authors.lastname: Johnson
authors.forename: Inga
authors.initials: I
authors.lastname: Peter
authors.forename: Hocine
authors.initials: H
authors.lastname: Tighiouart
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Ralston
authors.forename: Sabrina D
authors.initials: SD
authors.lastname: Craigo
authors.forename: Diana W
authors.initials: DW
authors.lastname: Bianchi
mesh_terms: D015193:Chorionic Villi Sampling / Q000009:adverse effects*; D041322:Chromosomes, Human, Y / Q000235:genetics; D004247:DNA / Q000097:blood*; D005260:Female; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics; D006801:Humans; D008297:Male; D011247:Pregnancy; D012680:Sensitivity and Specificity
chemical_list: D004247:DNA; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases