title: Trends in induction of labor at early-term gestation.
abstract: OBJECTIVE
  To determine the trends and racial differences in early-term induction of labor in the United States.
  
  
  METHODS
  Data from the National Center for Health Statistics were used to identify women eligible for induction between 37-42 weeks' gestation in the United States from 1991-2006. Annual early-term induction rates were calculated, and maternal race/ethnicity was classified into 4 groups. The change in frequency and odds of early-term induction stratified by race/ethnicity over time was assessed.
  
  
  RESULTS
  Among 39.2 million eligible women, early-term induction rates increased from 2.0% to 8.0% (P < .01) over 16 years. Cross-sectional and annual early-term induction rates were highest for non-Hispanic white women during the study period (P < .01). After adjusting for confounding factors, the odds of any early-term induction were highest (P < .01) and rose most rapidly (P < .01) among non-Hispanic white women compared with women from other racial/ethnic groups.
  
  
  CONCLUSIONS
  In the United States, early-term induction rates rose significantly and were highest among non-Hispanic white women.
authors.affiliation: Institute for Healthcare Studies, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. k-murthy@northwestern.edu
authors.forename: Karna
authors.initials: K
authors.lastname: Murthy
authors.forename: William A
authors.initials: WA
authors.lastname: Grobman
authors.forename: Todd A
authors.initials: TA
authors.lastname: Lee
authors.forename: Jane L
authors.initials: JL
authors.lastname: Holl
mesh_terms: D000328:Adult; D002585:Cesarean Section / Q000639:trends; D005260:Female; D005865:Gestational Age; D006801:Humans; D007751:Labor, Induced / Q000639:trends*; D011247:Pregnancy; D014481:United States