title: Prediction of spontaneous preterm birth using fetal fibronectin in women with a low-lying placenta.
abstract: OBJECTIVE
  To determine the effect of a low-lying placenta on the concentration of quantitative fetal fibronectin (qfFN) in the cervicovaginal fluid (CVF), and predictive accuracy for spontaneous preterm birth in asymptomatic high-risk women (18+0-24+0weeks gestation).
  
  
  METHODS
  Median concentrations of qfFN were compared in women who had a low-lying placenta, covering the cervical os (n = 61) to matched controls (n= 61) without a low-lying placenta. Proportions of women with raised qfFN concentrations (>10 ng/ml), and false positive and negative rates (FPR and FNR) for spontaneous preterm delivery were also compared.
  
  
  RESULTS
  The median concentration of qfFN in women with low-lying placenta was 5.0 ng/mL, compared with 6.0 ng/mL in controls. Proportion of women with raised levels (>10 ng/mL), positive levels (>50 ng/mL) and very high levels (>200 ng/mL) were similar in both groups (62.3% versus 59.0%, 16.3% versus 22.0% and 6.5% versus 4.9%, p > 0.05 for all thresholds). The FPR and FNR rate for delivery before 34 and 37 weeks were also comparable (FPR 90.0% versus 85.7% and 80.0% versus 78.6%; FNR 5.8% versus 4.3% and 9.8% versus 8.5%).
  
  
  CONCLUSIONS
  CVF qfFN concentrations in asymptomatic high-risk women are not affected by the presence of a low-lying placenta.
authors.affiliation: a King's College London , London , England , UK and.
authors.forename: Laura
authors.initials: L
authors.lastname: van der Krogt
authors.affiliation: b Division of Women's Health , King's College London, Women's Health Academic Centre, King's Health Partners, St Thomas' Hospital , London , England , UK.
authors.forename: Natasha L
authors.initials: NL
authors.lastname: Hezelgrave
authors.affiliation: b Division of Women's Health , King's College London, Women's Health Academic Centre, King's Health Partners, St Thomas' Hospital , London , England , UK.
authors.forename: Paul T
authors.initials: PT
authors.lastname: Seed
authors.affiliation: b Division of Women's Health , King's College London, Women's Health Academic Centre, King's Health Partners, St Thomas' Hospital , London , England , UK.
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Shennan
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D016022:Case-Control Studies; D003661:Decision Support Techniques; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D005353:Fibronectins / Q000378:metabolism*; D006801:Humans; D010923:Placenta Previa / Q000378:metabolism*; D011247:Pregnancy; D047928:Premature Birth / Q000175:diagnosis* / Q000209:etiology / Q000378:metabolism; D011446:Prospective Studies
chemical_list: D015415:Biomarkers; C403421:FFN protein, human; D005353:Fibronectins
keywords: Fetal fibronectin; low-lying placenta; preterm birth