title: Prolonged labor in nulliparas: lessons from the active management of labor.
abstract: OBJECTIVE
  To define factors causing prolonged labor in nulliparous women undergoing active management of labor.
  
  
  METHODS
  We included all nulliparas delivered during 1990-1994 with spontaneous onset of labor lasting more than 12 hours, singleton gestation, cephalic presentation, and labor at greater than 37 weeks. Each patient was matched with the next nulliparous woman who delivered with a labor lasting less than 12 hours and who fulfilled the same inclusion criteria. Subjects were managed according to the previously described active management of labor protocol from The National Maternity Hospital, Dublin.
  
  
  RESULTS
  In the 5-year period, 9018 nulliparas met inclusion criteria, with 147 (1.6%) having prolonged labor. Prolonged labor was due to inefficient uterine action in 65%, persistent occipitoposterior position in 24%, and cephalopelvic disproportion in 11% of cases. Univariate analysis showed statistically significant (P < .05) differences in maternal body mass index, cervical dilation on admission, oxytocin use, epidural use, placement of epidural at less than 2 cm of dilation, and birth weight between these study groups. On multivariate conditional logistic regression analysis, the following were significant independent predictors for having a prolonged labor (odds ratios with 95% confidence intervals presented): 3.1 (1.3-7.3) for cervical dilation less than 2 cm on admission, 42.7 (7.5-242.0) for early epidural placement, 5.1 (1.9-13.7) for epidural placement at greater than or equal to 2 cm, and 10.2 (3.6-29.4) for birth weight greater than 4000 g.
  
  
  CONCLUSIONS
  Less-advanced cervical dilation on admission and epidural use, especially when placed early, are strongly associated with prolonged labor.
authors.affiliation: Department of Obstetrics and Gynecology, Tufts University School of Medicine, New England Medical Center, Boston, Massachusetts, USA.
authors.forename: F D
authors.initials: FD
authors.lastname: Malone
authors.forename: M
authors.initials: M
authors.lastname: Geary
authors.forename: D
authors.initials: D
authors.lastname: Chelmow
authors.forename: J
authors.initials: J
authors.lastname: Stronge
authors.forename: P
authors.initials: P
authors.lastname: Boylan
authors.forename: M E
authors.initials: ME
authors.lastname: D'Alton
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D007743:Labor, Obstetric; D016015:Logistic Models; D015999:Multivariate Analysis; D016017:Odds Ratio; D010298:Parity; D011247:Pregnancy; D011256:Pregnancy Outcome; D013997:Time Factors