title: Short interpregnancy intervals in the United States.
abstract: OBJECTIVE
  To investigate the prevalence and correlates of short interpregnancy intervals in the United States.
  
  
  METHODS
  We analyzed pregnancy data from a nationally representative sample of 12,279 women from the 2006-2010 National Survey of Family Growth. We limited our sample to second and higher-order births within 5 years of the interview. Interpregnancy intervals were calculated as the interval between the delivery date of the preceding live birth and the conception date of the index pregnancy, with short interpregnancy intervals defined as intervals less than 18 months. We used simple and multivariate logistic regression analyses to examine associations between short interpregnancy intervals and maternal demographic and childbearing characteristics, including pregnancy intention.
  
  
  RESULTS
  Among the 2,253 pregnancies in our sample, one third (35%) were conceived within 18 months of a previous birth. After adjusting for sociodemographic and childbearing characteristics, women were significantly more likely to have a short interpregnancy interval if they were aged 15-19 years or married at the time of conception of the index pregnancy, initiated childbearing after age 30 years, or reported the pregnancy as unintended. Short interpregnancy intervals were more likely to be intended among more advantaged women (married, non-Hispanic white, college-educated, or non-Medicaid delivery). We estimate that preventing unintended pregnancies would reduce the proportion of short interpregnancy intervals from 35% to 23%.
  
  
  CONCLUSIONS
  Providing counseling about the potential negative consequences of short interpregnancy intervals and improving women's contraceptive use to reduce rates of unintended pregnancy likely would reduce the proportion of short interpregnancy interval pregnancies in the United States.
  
  
  METHODS
  II.
authors.affiliation: Department of Demography, University of California, Berkeley, Berkeley, California; and the Guttmacher Institute, Research Division, New York, New York.
authors.forename: Alison
authors.initials: A
authors.lastname: Gemmill
authors.forename: Laura Duberstein
authors.initials: LD
authors.lastname: Lindberg
mesh_terms: D000293:Adolescent; D000328:Adult; D001721:Birth Intervals / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008423:Maternal Age; D010298:Parity; D011247:Pregnancy; D015995:Prevalence; D017584:Reproductive History; D012307:Risk Factors; D013997:Time Factors; D014481:United States; D055815:Young Adult