title: Maternal plasma cell-free DNA in the prediction of pre-eclampsia.
abstract: OBJECTIVE
  To examine whether maternal plasma concentrations of total cell-free (cf)DNA and fetal fraction at 11-13 and 20-24 weeks' gestation in pregnancies that subsequently develop pre-eclampsia (PE) are different from those without this complication.
  
  
  METHODS
  Total cfDNA and fetal fraction were measured in 20 cases of early PE requiring delivery at < 34 weeks, in 20 cases of late PE with delivery at ≥ 34 weeks and in 200 normotensive controls, at 11-13 and 20-24 weeks' gestation. Total cfDNA and fetal fraction measured at 11-13 weeks were converted to multiples of the median (MoM), corrected for maternal characteristics and gestational age. The distributions of total cfDNA and fetal fraction at 20-24 weeks were expressed as MoM of values at 11-13 weeks. The Mann-Whitney U-test was used to determine the significance of differences in the median values in each outcome group relative to that in the controls.
  
  
  RESULTS
  In the early-PE group at 11-13 weeks, compared with controls, there was a significant increase in median total cfDNA (2104 genome equivalents (GE)/mL vs 1590 GE/mL) and a decrease in median fetal fraction (6.8% vs 8.7%). In the late-PE group at 20-24 weeks, compared with controls, there was a significant decrease in median fetal fraction (8.2% vs 9.6%). These significant differences between groups were not observed when the values were converted to MoM.
  
  
  CONCLUSIONS
  Measurements of total cfDNA and fetal fraction in maternal plasma at 11-13 and 20-24 weeks are not predictive of PE.
authors.affiliation: Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, UK.
authors.forename: D L
authors.initials: DL
authors.lastname: Rolnik
authors.forename: N
authors.initials: N
authors.lastname: O'Gorman
authors.forename: M
authors.initials: M
authors.lastname: Fiolna
authors.forename: D
authors.initials: D
authors.lastname: van den Boom
authors.forename: K H
authors.initials: KH
authors.lastname: Nicolaides
authors.forename: L C
authors.initials: LC
authors.lastname: Poon
mesh_terms: D000328:Adult; D001241:Aspirin / Q000627:therapeutic use*; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D002474:Cell-Free System; D018568:Crown-Rump Length; D004247:DNA / Q000097:blood*; D005260:Female; D006801:Humans; D008131:London; D008423:Maternal Age; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D011225:Pre-Eclampsia / Q000097:blood* / Q000175:diagnosis; D011237:Predictive Value of Tests; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D018570:Risk Assessment; D006113:United Kingdom
chemical_list: D015415:Biomarkers; D010975:Platelet Aggregation Inhibitors; D004247:DNA; D001241:Aspirin
keywords: DNA; cell free; pre-eclampsia