title: Maternal admission characteristics as risk factors for preterm birth.
abstract: OBJECTIVE
  The aim of this study is to identify a subset of women presenting with preterm labor not responding upon tocolytic therapy, eventually resulting in preterm birth.
  
  
  METHODS
  The maternal admission characteristics of 185 women with preterm labor receiving tocolysis were analysed for risk factors that could predict which women will deliver within 48 h after the start of tocolysis, or before 34 weeks gestation. Univariate analysis and multivariate logistic regression analysis was performed.
  
  
  RESULTS
  Logistic regression analysis identified the following risk factors for delivery within 48 h after the start of tocolysis: cervical dilatation at admission (odds ratio (OR, cm(-1)) 1.47; 95% confidence interval (CI), 1.44-1.49), elevated leukocyte count at admission (per 10(3) leukocytes/mm(3)) (OR 1.27; 95% CI, 1.26-1.28), use of nifedipine (OR 0.49; 95% CI, 0.26-0.49), and developing signs suggestive of chorioamnionitis following admission (OR 2.12; 95% CI, 1.04-4.33). For delivery before 34 weeks of gestation the following risk factors were identified: use of steroids (OR 5.87; 95% CI, 2.34-14.7), use of nifedipine (OR 0.46; 95% CI, 0.27-0.85), developing signs suggestive of chorioamnionitis following admission (OR 10.6; 95% CI, 3.1-35.9), and preterm premature rupture of the membranes (OR 12; 95% CI, 4.1-35.2).
  
  
  CONCLUSIONS
  Risk factors associated for delivery within 48 h after starting tocolysis are: cervical dilatation at admission, elevated leukocyte count at admission, and developing signs suggestive of chorioamnionitis following admission. Use of nifedipine was associated with a delay of delivery >48 h. Risk factors associated for delivery within 34 weeks gestation are: use of steroids, developing signs suggestive of chorioamnionitis following admission, and ruptured membranes. Use of nifedipine was associated with a delay >34 weeks.
authors.affiliation: Department of Obstetrics and Gynecology, Free University Hospital, Amsterdam, The Netherlands. hoog.pap@wxs.nl
authors.forename: Dimitrios N M
authors.initials: DN
authors.lastname: Papatsonis
authors.forename: Herman P
authors.initials: HP
authors.lastname: van Geijn
authors.forename: Otto P
authors.initials: OP
authors.lastname: Bleker
authors.forename: Herman J
authors.initials: HJ
authors.lastname: Ader
authors.forename: Gustaaf A
authors.initials: GA
authors.lastname: Dekker
mesh_terms: D000328:Adult; D016001:Confidence Intervals; D005260:Female; D005500:Follow-Up Studies; D005865:Gestational Age; D006785:Hospitals, University; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D007234:Infant, Premature; D007747:Labor Stage, First / Q000187:drug effects; D016015:Logistic Models; D009426:Netherlands; D009543:Nifedipine / Q000627:therapeutic use; D007752:Obstetric Labor, Premature / Q000453:epidemiology* / Q000517:prevention & control*; D016017:Odds Ratio; D010343:Patient Admission; D011247:Pregnancy; D011256:Pregnancy Outcome; D012307:Risk Factors; D012312:Ritodrine / Q000627:therapeutic use; D015145:Tocolysis / Q000379:methods*; D015149:Tocolytic Agents / Q000627:therapeutic use*
chemical_list: D015149:Tocolytic Agents; D012312:Ritodrine; D009543:Nifedipine