title: Does the rate of cervical shortening after cerclage predict preterm birth?
abstract: OBJECTIVE
  The objective of this study is to evaluate whether the rate of cervical shortening after cerclage can predict spontaneous preterm birth (SPTB).
  
  
  METHODS
  Women who had cervical length (CL) assessments after cerclage placement were identified. The rate of cervical shortening and its relationship with SPTB was established using a generalized linear regression model. Secondary outcomes included relationship between cervical shortening and risk of SPTB in those with a post-cerclage CL <25 mm versus ≥25 mm at 18-20 weeks; and the rate of cervical shortening in women who delivered preterm compared with those who delivered at term.
  
  
  RESULTS
  One hundred thirty-four patients were included and 30 (22.4%) delivered at <36 weeks. A rate of cervical shortening of 1 mm/week conferred a risk of SPTB of 22%. Among women with cerclage who had a CL <25 mm at 18-20 weeks, 1 mm/week of cervical shortening was associated with a 59% risk of SPTB. Patients with cerclage who delivered at term had a slower rate of cervical shortening compared to those who delivered preterm (0.62 mm versus 1.40 mm per week, p = 0.008).
  
  
  CONCLUSIONS
  The rate of cervical shortening after cerclage placement is associated with the risk of SPTB. Sonographic surveillance of the rate of cervical shortening may be useful in assessing risk for SPTB in patients with cerclage.
authors.affiliation: a Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology , and.
authors.forename: Daphnie
authors.initials: D
authors.lastname: Drassinower
authors.affiliation: a Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology , and.
authors.forename: Joy
authors.initials: J
authors.lastname: Vink
authors.affiliation: a Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology , and.
authors.forename: Noelia
authors.initials: N
authors.lastname: Zork
authors.affiliation: a Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology , and.
authors.forename: Cara
authors.initials: C
authors.lastname: Pessel
authors.affiliation: b Department of Obstetrics and Gynecology , Columbia University Medical Center, New York, NY, USA , and.
authors.forename: Kavita
authors.initials: K
authors.lastname: Vani
authors.affiliation: a Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology , and.
authors.forename: Sara G
authors.initials: SG
authors.lastname: Brubaker
authors.affiliation: b Department of Obstetrics and Gynecology , Columbia University Medical Center, New York, NY, USA , and.|c Department of Epidemiology , Joseph L. Mailman School of Public Health, New York, NY, USA.
authors.forename: Cande V
authors.initials: CV
authors.lastname: Ananth
mesh_terms: D000328:Adult; D023802:Cerclage, Cervical; D054791:Cervical Length Measurement; D015331:Cohort Studies; D005260:Female; D006801:Humans; D016014:Linear Models; D009518:New York / Q000453:epidemiology; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology* / Q000517:prevention & control; D012189:Retrospective Studies; D018570:Risk Assessment
keywords: Preterm delivery; rate of change; short cervix