title: Smoking in pregnancy is associated with increased total maternal serum cell-free DNA levels.
abstract: OBJECTIVE
  Cell-free DNA is a marker of cellular apoptosis and necrosis. We wished to determine if maternal smoking affects maternal and fetal serum cell-free DNA levels.
  
  
  METHODS
  Case-control sets of stored second-trimester serum-screening samples from 27 smoking and 90 nonsmoking pregnant women were developed. Smoking status was confirmed by measuring serum cotinine levels. Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and DYS1 levels were determined using real-time polymerase chain reaction (PCR) to measure total and fetal cell-free DNA, respectively. At delivery, medical records were reviewed to confirm gender and determine other factors that could affect DNA values.
  
  
  RESULTS
  Smoking was associated with significantly elevated GAPDH levels compared with nonsmokers (median: 97,662 genome equivalents (GE)/mL vs 38,217 GE/mL; p = 0.018). DYS1 levels were not statistically significantly elevated in smokers (p = 0.29). Other factors that affected DYS1 levels included maternal age in nonsmokers only (r(2) = 0.30, p = 0.013) and maternal Synthroid use (p = 0.0045)
  
  
  CONCLUSIONS
  Pregnant smokers have threefold higher levels of total cell-free DNA compared with pregnant nonsmokers. Maternal age and Synthroid exposure may also affect circulating cell-free fetal DNA levels.
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Tufts-New England Medical Center, Boston, MA 02111, USA. aurato@tufts-nemc.org
authors.forename: Adam C
authors.initials: AC
authors.lastname: Urato
authors.forename: Inga
authors.initials: I
authors.lastname: Peter
authors.forename: Jacob
authors.initials: J
authors.lastname: Canick
authors.forename: Geralyn
authors.initials: G
authors.lastname: Lambert-Messerlian
authors.forename: Andrea
authors.initials: A
authors.lastname: Pulkkinen
authors.forename: George
authors.initials: G
authors.lastname: Knight
authors.forename: Young-Ju
authors.initials: YJ
authors.lastname: Jeong
authors.forename: Kirby L
authors.initials: KL
authors.lastname: Johnson
authors.forename: Diana W
authors.initials: DW
authors.lastname: Bianchi
mesh_terms: D000328:Adult; D017209:Apoptosis; D016022:Case-Control Studies; D003367:Cotinine / Q000097:blood*; D004247:DNA / Q000097:blood*; D005260:Female; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000097:blood; D006801:Humans; D009336:Necrosis; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012907:Smoking / Q000097:blood*
chemical_list: D004247:DNA; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D003367:Cotinine