title: Fetal fibronectin status and cervical length in women with threatened preterm labor and the effectiveness of maintenance tocolysis.
abstract: OBJECTIVE
  To assess the effect of maintenance tocolysis in women who are at high or low risk for preterm delivery according to fetal fibronectin (fFN) status and cervical length (CL).
  
  
  METHODS
  We compared the risk of preterm delivery in fFN pos and fFN neg women and in women with a CL <15 mm and ≥15 mm, by using the Cox regression. Differences between the effectiveness of maintenance tocolysis in high- and low-risk women were assessed by using an interaction term.
  
  
  RESULTS
  122 fFN tests were taken, of which 50 were fFN pos. CL was measured in 236 women, of whom 52 women had a CL <15 mm. The median gestational age at delivery was lower in fFN pos women; fFN pos women had a higher hazard for preterm delivery at any point of time (HR 4.7; 95% CI 2.9 to 7.6). Comparable results were seen for CL. Neither fFN status nor CL did alter the effect of maintenance tocolysis, which was ineffective in the total randomized group, on the risk of preterm delivery (p for interaction = 0.87 for fFN and 0.18 for CL).
  
  
  CONCLUSIONS
  Maintenance tocolytic therapy with nifedipine is ineffective and not dependent on fFN or CL status.
authors.affiliation: a Department of Obstetrics and Gynecology , Radboud University Medical Center , Nijmegen , The Netherlands .
authors.forename: Carolien
authors.initials: C
authors.lastname: Roos
authors.affiliation: b Department of Clinical Chemistry and Haematology , University Medical Center Utrecht , Utrecht , The Netherlands .
authors.forename: Jolande Y
authors.initials: JY
authors.lastname: Vis
authors.affiliation: c Department of Obstetrics and Gynecology , Maastricht University Medical Center, GROW School for Oncology and Developmental Biology , Maastricht , The Netherlands .
authors.forename: Hubertina C J
authors.initials: HC
authors.lastname: Scheepers
authors.affiliation: d Department of Obstetrics and Gynecology , Leiden University Medical Center , Leiden , The Netherlands .
authors.forename: Kitty W M
authors.initials: KW
authors.lastname: Bloemenkamp
authors.affiliation: e Department of Obstetrics and Gynecology , Erasmus Medical Center , Rotterdam , The Netherlands .
authors.forename: Hans J J
authors.initials: HJ
authors.lastname: Duvekot
authors.affiliation: f Department of Obstetrics and Gynecology , Isala Clinics , Zwolle , The Netherlands .
authors.forename: Jim
authors.initials: J
authors.lastname: van Eyck
authors.affiliation: g Department of Obstetrics and Gynecology , VU Medical Center , Amsterdam , The Netherlands .
authors.forename: Christianne
authors.initials: C
authors.lastname: de Groot
authors.affiliation: h Department of Neonatology , Academic Medical Center , Amsterdam , The Netherlands .
authors.forename: Joke H
authors.initials: JH
authors.lastname: Kok
authors.affiliation: i Clinical Research Unit , Academic Medical Center , Amsterdam , The Netherlands .
authors.forename: Brent C
authors.initials: BC
authors.lastname: Opmeer
authors.affiliation: j Department of Obstetrics and Gynecology , University Medical Center Utrecht , Utrecht , The Netherlands .
authors.forename: Martijn A
authors.initials: MA
authors.lastname: Oudijk
authors.affiliation: k Department of Obstetrics and Gynecology , Amphia Hospital , Breda , The Netherlands .
authors.forename: Dimitri N M
authors.initials: DN
authors.lastname: Papatsonis
authors.affiliation: l Department of Obstetrics and Gynecology , Máxima Medical Center , Veldhoven , The Netherlands .
authors.forename: Martina M
authors.initials: MM
authors.lastname: Porath
authors.affiliation: m Department of Obstetrics and Gynecology , University Medical Center , Groningen , The Netherlands .
authors.forename: Krystyna
authors.initials: K
authors.lastname: Sollie
authors.affiliation: c Department of Obstetrics and Gynecology , Maastricht University Medical Center, GROW School for Oncology and Developmental Biology , Maastricht , The Netherlands .
authors.forename: Marc E A
authors.initials: ME
authors.lastname: Spaanderman
authors.affiliation: a Department of Obstetrics and Gynecology , Radboud University Medical Center , Nijmegen , The Netherlands .
authors.forename: Fred K
authors.initials: FK
authors.lastname: Lotgering
authors.affiliation: n Department of Obstetrics and Gynecology , Academic Medical Center , Amsterdam , The Netherlands , and.
authors.forename: Joris A M
authors.initials: JA
authors.lastname: van der Post
authors.affiliation: o The Robinson Institute, School of Paediatrics and Reproductive Health, University of Adelaide , Adelaide , Australia.
authors.forename: Ben Willem J
authors.initials: BW
authors.lastname: Mol
mesh_terms: D000328:Adult; D054791:Cervical Length Measurement; D005260:Female; D005353:Fibronectins / Q000032:analysis*; D006801:Humans; D009543:Nifedipine / Q000627:therapeutic use; D007752:Obstetric Labor, Premature / Q000517:prevention & control*; D011247:Pregnancy; D015145:Tocolysis / Q000706:statistics & numerical data*; D015149:Tocolytic Agents / Q000627:therapeutic use; D055815:Young Adult
chemical_list: C403421:FFN protein, human; D005353:Fibronectins; D015149:Tocolytic Agents; D009543:Nifedipine
keywords: Cervical length; fetal fibronectin; maintenance tocolysis