title: Management of fetal malposition in the second stage of labor: a propensity score analysis.
abstract: OBJECTIVE
  We sought to determine the factors associated with selection of rotational instrumental vs cesarean delivery to manage persistent fetal malposition, and to assess differences in adverse neonatal and maternal outcomes following delivery by rotational instruments vs cesarean delivery.
  
  
  METHODS
  We conducted a retrospective cohort study over a 5-year period in a tertiary United Kingdom obstetrics center. In all, 868 women with vertex-presenting, single, liveborn infants at term with persistent malposition in the second stage of labor were included. Propensity score stratification was used to control for selection bias: the possibility that obstetricians may systematically select more difficult cases for cesarean delivery. Linear and logistic regression models were used to compare maternal and neonatal outcomes for delivery by rotational forceps or ventouse vs cesarean delivery, adjusting for propensity scores.
  
  
  RESULTS
  Increased likelihood of rotational instrumental delivery was associated with lower maternal age (odds ratio [OR], 0.95; P < .01), lower body mass index (OR, 0.94; P < .001), lower birthweight (OR, 0.95; P < .01), no evidence of fetal compromise at the time of delivery (OR, 0.31; P < .001), delivery during the daytime (OR, 1.45; P < .05), and delivery by a more experienced obstetrician (OR, 7.21; P < .001). Following propensity score stratification, there was no difference by delivery method in the rates of delayed neonatal respiration, reported critical incidents, or low fetal arterial pH. Maternal blood loss was higher in the cesarean group (295.8 ± 48 mL, P < .001).
  
  
  CONCLUSIONS
  Rotational instrumental delivery is often regarded as unsafe. However, we find that neonatal outcomes are no worse once selection bias is accounted for, and that the likelihood of severe obstetric hemorrhage is reduced. More widespread training of obstetricians in rotational instrumental delivery should be considered, particularly in light of rising cesarean delivery rates.
authors.affiliation: Office of Population Research, Princeton University, Princeton, NJ.
authors.forename: Abigail R
authors.initials: AR
authors.lastname: Aiken
authors.affiliation: Department of Obstetrics and Gynecology, University of Cambridge, and National Institute of Health Research Cambridge Comprehensive Biomedical Research Center, England, United Kingdom. Electronic address: cema2@cam.ac.uk.
authors.forename: Catherine E
authors.initials: CE
authors.lastname: Aiken
authors.affiliation: Department of Obstetrics and Gynecology, University of Cambridge, and National Institute of Health Research Cambridge Comprehensive Biomedical Research Center, England, United Kingdom.
authors.forename: Medhat S
authors.initials: MS
authors.lastname: Alberry
authors.affiliation: Department of Obstetrics and Gynecology, University of Cambridge, and National Institute of Health Research Cambridge Comprehensive Biomedical Research Center, England, United Kingdom.
authors.forename: Jeremy C
authors.initials: JC
authors.lastname: Brockelsby
authors.affiliation: Red McCombs School of Business and Division of Statistics and Scientific Computation, University of Texas at Austin, Austin, TX.
authors.forename: James G
authors.initials: JG
authors.lastname: Scott
mesh_terms: D000328:Adult; D002585:Cesarean Section / Q000009:adverse effects; D015331:Cohort Studies; D005113:Extraction, Obstetrical / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007746:Labor Presentation; D007748:Labor Stage, Second; D016014:Linear Models; D016015:Logistic Models; D016017:Odds Ratio; D063868:Patient Outcome Assessment; D011247:Pregnancy; D057216:Propensity Score; D012189:Retrospective Studies
keywords: cesarean delivery; delivery; fetal malposition; intrapartum care; operative vaginal delivery