title: Risk stratification with cervical length and fetal fibronectin in women with threatened preterm labor before 34 weeks and not delivering within 7 days.
abstract: OBJECTIVE
  To stratify the risk of spontaneous preterm delivery using cervical length (CL) and fetal fibronectin (fFN) in women with threatened preterm labor who remained pregnant after 7 days.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  Nationwide cohort of women with threatened preterm labor from the Netherlands.
  
  
  METHODS
  Women with threatened preterm labor between 24 and 34 weeks with a valid CL and fFN measurement and remaining pregnant 7 days after admission.
  
  
  METHODS
  Kaplan-Meier and Cox proportional hazards models were used to estimate cumulative percentages and hazard ratios (HR) for spontaneous delivery.
  
  
  METHODS
  Spontaneous delivery between 7 and 14 days after initial presentation and spontaneous preterm delivery before 34 weeks.
  
  
  RESULTS
  The risk of delivery between 7 and 14 days was significantly increased for women with a CL < 15 mm or a CL ≥15 to <30 mm and a positive fFN, compared with women with a CL ≥30 mm: HR 22.3 [95% confidence interval (CI) 2.6-191] and 14 (95% CI 1.8-118), respectively. For spontaneous preterm delivery before 34 weeks the risk was increased for women with a CL < 15 mm [HR 6.3 (95% CI 2.6-15)] or with a CL ≥15 to <30 mm with either positive fFN [HR 3.6 (95% CI 1.5-8.7)] or negative fFN [HR 3.0 (95% CI 1.2-7.1)] compared with women with a CL ≥ 30 mm.
  
  
  CONCLUSIONS
  In women remaining pregnant 7 days after threatened preterm labor, CL and fFN results can be used in risk stratification for spontaneous delivery.
authors.affiliation: Department of Obstetrics and Gynecology, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Frederik J R
authors.initials: FJR
authors.lastname: Hermans
authors.affiliation: Department of Obstetrics and Gynecology, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Merel M C
authors.initials: MMC
authors.lastname: Bruijn
authors.affiliation: Department of Clinical Chemistry and Hematology, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Jolande Y
authors.initials: JY
authors.lastname: Vis
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital Maastricht, Maastricht, the Netherlands.
authors.forename: Femke F
authors.initials: FF
authors.lastname: Wilms
authors.affiliation: Department of Obstetrics and Gynecology, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Martijn A
authors.initials: MA
authors.lastname: Oudijk
authors.affiliation: Department of Obstetrics and Gynecology, Máxima Medical Center, Veldhoven, the Netherlands.
authors.forename: Martina M
authors.initials: MM
authors.lastname: Porath
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital Maastricht, Maastricht, the Netherlands.
authors.forename: Hubertina C J
authors.initials: HCJ
authors.lastname: Scheepers
authors.affiliation: Department of Obstetrics and Gynecology, Leiden University Medical Center, Leiden, the Netherlands.
authors.forename: Kitty W M
authors.initials: KWM
authors.lastname: Bloemenkamp
authors.affiliation: Department of Obstetrics and Gynecology, VU University Medical Center, Amsterdam, the Netherlands.
authors.forename: Caroline J
authors.initials: CJ
authors.lastname: Bax
authors.affiliation: Department of Obstetrics and Gynecology, Erasmus Medical Center, Rotterdam, the Netherlands.
authors.forename: Jérôme M J
authors.initials: JMJ
authors.lastname: Cornette
authors.affiliation: Department of Obstetrics and Gynecology, Isala Clinics, Zwolle, the Netherlands.
authors.forename: Bas W A
authors.initials: BWA
authors.lastname: Nij Bijvanck
authors.affiliation: Department of Obstetrics and Gynecology, University Medical Center Groningen, Groningen, the Netherlands.
authors.forename: Maureen T M
authors.initials: MTM
authors.lastname: Franssen
authors.affiliation: Department of Obstetrics and Gynecology, Radboud University Nijmegen Medical Center, Nijmegen, the Netherlands.
authors.forename: Frank P H A
authors.initials: FPHA
authors.lastname: Vandenbussche
authors.affiliation: Department of Obstetrics and Gynecology, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Marjolein
authors.initials: M
authors.lastname: Kok
authors.affiliation: Department of Gynecology and Obstetrics, Northwestern University Medical School, Chicago, IL, USA.
authors.forename: William A
authors.initials: WA
authors.lastname: Grobman
authors.affiliation: Department of Obstetrics and Gynecology, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Joris A M
authors.initials: JAM
authors.lastname: Van Der Post
authors.affiliation: Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Patrick M M
authors.initials: PMM
authors.lastname: Bossuyt
authors.affiliation: Clinical Research Unit, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Brent C
authors.initials: BC
authors.lastname: Opmeer
authors.affiliation: Robinson Research Institute, School of Pediatrics and Reproductive Health, University of Adelaide, Adelaide, SA, Australia.
authors.forename: Ben Willem J
authors.initials: BWJ
authors.lastname: Mol
authors.affiliation: Department of Obstetrics and Gynecology, Academic Medical Center, Amsterdam, the Netherlands.|Julius Center for Healthcare Research and Primary Care, University Medical Center Utrecht, Utrecht, the Netherlands.|Stanford Prevention Research Center, Stanford University, Stanford, CA, USA.
authors.forename: Ewoud
authors.initials: E
authors.lastname: Schuit
authors.affiliation: Department of Obstetrics and Gynecology, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Gert-Jan
authors.initials: GJ
authors.lastname: Van Baaren
mesh_terms: D000328:Adult; D054791:Cervical Length Measurement; D005260:Female; D005353:Fibronectins / Q000097:blood*; D006801:Humans; D009426:Netherlands / Q000453:epidemiology; D007752:Obstetric Labor, Premature / Q000097:blood / Q000453:epidemiology*; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018570:Risk Assessment; D047929:Term Birth
chemical_list: D005353:Fibronectins
keywords: Threatened preterm labor; cervical length; fetal fibronectin; prediction; pregnancy complications; risk; spontaneous preterm delivery