title: What is predictive of preterm delivery in the first trimester: isthmus or cervical length?
abstract: OBJECTIVE
  This study aims to evaluate the utility of first trimester cervical ultrasonography in predicting preterm delivery by separate analysis of measurements of cervical and isthmus length.
  
  
  METHODS
  This is a cohort study based on data collected prospectively on singletons between 1 July 2011 and 1 February 2013. Mean cervical, isthmus and cervico-isthmic complex length were measured for deliveries before and after 37 weeks.
  
  
  RESULTS
  A total of 1494 pregnancies were analysed, including 51 cases of spontaneous preterm delivery (3.4%). The cervico-isthmic complex in the first trimester was significantly shorter in patients who delivered before term (43.8 mm vs 47.5 mm, p = 0.04). This difference is related to differences in length at the isthmus (10.7 mm vs 14.1 mm, p = 0.005) rather than at the cervix proper (34.5 mm vs 35.0 mm, p = 0.56).
  
  
  CONCLUSIONS
  Measurement of the cervico-isthmic complex enables detection of a number of patients who will go on to deliver before term. Further studies are necessary to confirm that isthmic length and not cervical length is predictive of preterm delivery.
authors.affiliation: Department of Obstetrics and Gynecology, Strasbourg University Teaching Hospital, Strasbourg, France. nicolas.sananes@chru-strasbourg.fr
authors.forename: Nicolas
authors.initials: N
authors.lastname: Sananès
authors.forename: Elodie
authors.initials: E
authors.lastname: Schuller
authors.forename: Adrien
authors.initials: A
authors.lastname: Gaudineau
authors.forename: Monique
authors.initials: M
authors.lastname: Kohler
authors.forename: Fernando
authors.initials: F
authors.lastname: Guerra
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Weingertner
authors.forename: Gabrielle
authors.initials: G
authors.lastname: Fritz
authors.forename: Brigitte
authors.initials: B
authors.lastname: Viville
authors.forename: Bruno
authors.initials: B
authors.lastname: Langer
authors.forename: Israël
authors.initials: I
authors.lastname: Nisand
authors.forename: Romain
authors.initials: R
authors.lastname: Favre
mesh_terms: D000328:Adult; D054791:Cervical Length Measurement / Q000379:methods*; D002584:Cervix Uteri / Q000000981:diagnostic imaging*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007752:Obstetric Labor, Premature / Q000000981:diagnostic imaging; D011237:Predictive Value of Tests; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D047928:Premature Birth / Q000000981:diagnostic imaging*; D011379:Prognosis; D016216:Ultrasonography, Prenatal; D014599:Uterus / Q000000981:diagnostic imaging*