title: U.S. national trends in labor induction, 1989-1998.
abstract: OBJECTIVE
  To examine the epidemiology of labor induction in the United States.
  
  
  METHODS
  We used U.S. natality data from 1989 to 1998 and examined the rate of labor induction by year, geographic region, maternal characteristics and pregnancy complications.
  
  
  RESULTS
  Between 1990 and 1998, the rate of labor induction increased from 9.5% to 19.4% of all births nationwide. However, the induction rate varied widely by state. White race, higher education and early initiation of prenatal care were associated with a higher rate of induction. For all gestational ages, a significantly increased induction rate occurred during the study period. The increase for clinically indicated induction was significantly slower than the overall increase, suggesting that elective induction has risen much more rapidly.
  
  
  CONCLUSIONS
  The rate of induction of labor more than doubled in the U.S. nationwide in the decade from 1989 to 1998. The increased use of labor induction may be attributable to both clinically indicated and elective induction.
authors.affiliation: Epidemiology Branch, National Institute of Child Health and Human Development, National Institutes of Health, NIH Building 6100, Room 7B03, Bethesda, MD 20892, USA. jim_zhang@nih.gov
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.forename: Michael K
authors.initials: MK
authors.lastname: Yancey
authors.forename: Cassandra E
authors.initials: CE
authors.lastname: Henderson
mesh_terms: D000293:Adolescent; D000328:Adult; D004522:Educational Status; D005260:Female; D005865:Gestational Age; D006801:Humans; D007751:Labor, Induced / Q000706:statistics & numerical data / Q000639:trends*; D008423:Maternal Age; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology; D011295:Prenatal Care; D044469:Racial Groups; D012189:Retrospective Studies; D014481:United States / Q000453:epidemiology