title: Endocervical and high vaginal quantitative fetal fibronectin in predicting preterm birth.
abstract: OBJECTIVE
  Accurate prediction of spontaneous preterm birth (sPTB) is essential to target interventions. Fetal fibronectin (fFN) is a leading predictor. A quantitative fFN (qfFN) test has improved prediction, based on high vaginal swabs (HVS). It is not known how endocervical (ECS) fFN levels compare, or which has the best predictive value. Our principal aim was to determine the difference in fFN concentration between HVS and ECS and compare their ability to predict sPTB.
  
  
  METHODS
  Asymptomatic high risk women (18(+0)-30(+0) weeks gestation) had secretions sampled from the endocervix (ECS) and vaginal fornix (HVS), analyzed by the quantitative fFN analyzer (Hologic). Mean concentrations were compared; ROC curves were calculated using area under the curve (AUC) for prediction of delivery <30 and 37 weeks.
  
  
  RESULTS
  Mean HVS value was lower than ECS (80 ng/ml (SD142) versus 217 (SD 212) (p < 0.05). Predictive ability was similar: AUC of 0.92 and 0.94, respectively, for prediction of sPTB < 37 and 0.84 and 0.82 for <30 weeks.
  
  
  CONCLUSIONS
  Endocervical qfFN is higher than HVS and clinicians should avoid ECS if using traditional thresholds. ECS and HVS are both useful predictors, but require different threshold values. Further work is needed to determine whether ECS is a better and safe test to justify the difficulty in sampling.
authors.affiliation: Woman's Health Academic Centre, Kings College London , London , UK.
authors.forename: Katy
authors.initials: K
authors.lastname: Kuhrt
authors.forename: Christina
authors.initials: C
authors.lastname: Unwin
authors.forename: Natasha
authors.initials: N
authors.lastname: Hezelgrave
authors.forename: Paul
authors.initials: P
authors.lastname: Seed
authors.forename: Andrew
authors.initials: A
authors.lastname: Shennan
mesh_terms: D002584:Cervix Uteri / Q000737:chemistry*; D005260:Female; D005353:Fibronectins / Q000032:analysis*; D006801:Humans; D011237:Predictive Value of Tests; D011247:Pregnancy; D047928:Premature Birth; D014621:Vagina / Q000737:chemistry*
chemical_list: C403421:FFN protein, human; D005353:Fibronectins
keywords: Predictive test; premature labour; sampling site