title: Clinical and sonographic parameters at mid-trimester and the risk of cesarean delivery in low-risk nulliparas.
abstract: BACKGROUND
  To examine the potential clinical and sonographic parameters at mid-trimester that predict the risk of intrapartum cesarean delivery at term among low-risk nulliparas.
  
  
  METHODS
  This prospective study recruited nulliparas with singleton low-risk pregnancies at 20.0-24.0 weeks. Sonographic measurement of the cervical length and fetal biometry was performed. The data collected at enrollment included maternal age, measured weight at first prenatal visit to the hospital, current weight, height, fetal biometric parameters, and cervical length. A multivariate analysis was conducted, with control for known intra- and postpartum confounding factors associated with cesarean delivery, including sex of the fetus.
  
  
  RESULTS
  Based on multivariate analyses of 652 women, of all variables at mid-trimester, only maternal height was significantly associated with increased risk of cesarean delivery (61, 9.4%), whereas for intra- or postpartum variables, induction of labor, epidural analgesia, male gender, and nightshift delivery showed statistically significant association with the risk of cesarean delivery.
  
  
  CONCLUSIONS
  Maternal height and fetal gender, as measured at mid-trimester, are potential independent predictors for the risk of intrapartum cesarean delivery at term in low-risk nulliparas; however, sonographic measurements of the cervical length, fetal biometric ratio, maternal age, and current weight at mid-trimester were not predictive of cesarean delivery at term. © 2014 Wiley Periodicals, Inc. J Clin Ultrasound 43:235-242, 2015.
authors.affiliation: Departments of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Eun Ha
authors.initials: EH
authors.lastname: Jeong
authors.affiliation: Departments of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Kyo Hoon
authors.initials: KH
authors.lastname: Park
authors.affiliation: Departments of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Aeli
authors.initials: A
authors.lastname: Ryu
authors.affiliation: Departments of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Kyung Joon
authors.initials: KJ
authors.lastname: Oh
authors.affiliation: Departments of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Sung Youn
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Departments of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Ahra
authors.initials: A
authors.lastname: Kim
keywords: cervical length; cesarean delivery; low-risk; mid-trimester; nulliparas