title: Ability of cervical length to predict spontaneous preterm delivery in twin pregnancies using the receiver-operating characteristic curve analysis and an a priori cut-off value.
abstract: In this retrospective study based on cervical length (CL) measurements between 20 and 24 + 6 weeks, we examined the ability of CL to predict spontaneous preterm birth (SPTB) in 222 twin pregnancies using the receiver-operating curve (ROC) analysis and an a priori cut-off. CL predicted SPTB before 34 weeks. Using the ROC the selected cut-off was 37.5 mm. Positive predictive value (PPV) and negative predictive value (NPV) regarding SPTB before 34 weeks for 37.5 mm were 15.7% and 5.3% respectively. Using the 5th percentile, PPV and NPV regarding SPTB before 34 weeks for 24 mm were 41.7% and 91.4%, respectively. The 5th centile of CL measurements should be employed in clinical practice. CL measurement is an adequate screening tool for SPTB since it has a high NPV. Studies on CL measurement and SPTB should explain which methodology they adopted to obtain a cut-off value and the rationale of their choice.
authors.affiliation: a Department of Science for Woman and Child Health , University of Florence , Florence , Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Pasquini
authors.affiliation: a Department of Science for Woman and Child Health , University of Florence , Florence , Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Sisti
authors.affiliation: b Department of Gynecology , 401 General Military Hospital , Athens , Greece.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Nasioudis
authors.affiliation: c Department of Obstetrics and Gynecology , University of Perugia , Perugia , Italy.
authors.forename: Tomi
authors.initials: T
authors.lastname: Kanninen
authors.affiliation: a Department of Science for Woman and Child Health , University of Florence , Florence , Italy.
authors.forename: Flavia
authors.initials: F
authors.lastname: Sorbi
authors.affiliation: a Department of Science for Woman and Child Health , University of Florence , Florence , Italy.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Fambrini
authors.affiliation: a Department of Science for Woman and Child Health , University of Florence , Florence , Italy.
authors.forename: Irene
authors.initials: I
authors.lastname: Turrini
authors.affiliation: a Department of Science for Woman and Child Health , University of Florence , Florence , Italy.
authors.forename: Viola
authors.initials: V
authors.lastname: Seravalli
authors.affiliation: a Department of Science for Woman and Child Health , University of Florence , Florence , Italy.
authors.forename: Mariarosaria
authors.initials: M
authors.lastname: Di Tommaso
mesh_terms: D000328:Adult; D054791:Cervical Length Measurement; D005260:Female; D006801:Humans; D011247:Pregnancy; D059285:Pregnancy, Twin; D047928:Premature Birth / Q000000981:diagnostic imaging*; D012372:ROC Curve; D012189:Retrospective Studies
keywords: Cervical length; preterm birth; twin pregnancy