title: The changing pattern of prenatal care utilization in the United States, 1981-1995, using different prenatal care indices.
abstract: BACKGROUND
  Two measures traditionally used to examine adequacy of prenatal care indicate that prenatal care utilization remained unchanged through the 1980s and only began to rise slightly in the 1990s. In recent years, new measures have been developed that include a category for women who receive more than the recommended amount of care (intensive utilization).
  
  
  OBJECTIVE
  To compare the older and newer indices in the monitoring of prenatal care trends in the United States from 1981 to 1995, for the overall population and for selected subpopulations. Second, to examine factors associated with receiving intensive utilization.
  
  
  METHODS
  Cross-sectional and trend analysis of national birth records.
  
  
  METHODS
  The United States.
  
  
  METHODS
  All live births between 1981 and 1995 (N=54 million).
  
  
  METHODS
  Trends in prenatal care utilization, according to 4 indices (the older indices: the Institute of Medicine Index and the trimester that care began, and the newer indices: the R-GINDEX and the Adequacy of Prenatal Care Utilization Index). Multiple logistic regression was used to assess the risk of intensive prenatal care use in 1981 and 1995.
  
  
  RESULTS
  The newer indices showed a steadily increasing trend toward more prenatal care use throughout the study period (R-GINDEX, intensive or adequate use, 32.7% in 1981 to 47.1 % in 1995; the Adequacy of Prenatal Care Utilization Index, intensive use, 18.4% in 1981 to 28.8% in 1995), especially for intensive utilization. Women having a multiple birth were much more likely to have had intensive utilization in 1995 compared with 1981 (R-GINDEX, 22.8% vs 8.5%). Teenagers were more likely to begin care later than adults, but similar proportions of teens and adults had intensive utilization. Intensive use among low-risk women also increased steadily each year. Factors associated with a greater likelihood of receiving intensive use in 1981 and 1995 were having a multiple birth, primiparity, being married, and maternal age of 35 years or older.
  
  
  CONCLUSIONS
  The proportion of women who began care early and received at least the recommended number of visits increased between 1981 and 1995. This change was undetected by more traditional prenatal care indices. These increases have cost and practice implications and suggest a paradox since previous studies have shown that rates of preterm delivery and low birth weight did not improve during this time.
authors.affiliation: Centers for Disease Control and Prevention, National Center for Health Statistics, Hyattsville, MD 20782, USA. mdk1@cdc.gov
authors.forename: M D
authors.initials: MD
authors.lastname: Kogan
authors.forename: J A
authors.initials: JA
authors.lastname: Martin
authors.forename: G R
authors.initials: GR
authors.lastname: Alexander
authors.forename: M
authors.initials: M
authors.lastname: Kotelchuck
authors.forename: S J
authors.initials: SJ
authors.lastname: Ventura
authors.forename: F D
authors.initials: FD
authors.lastname: Frigoletto
mesh_terms: D000293:Adolescent; D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D019538:Health Care Surveys / Q000379:methods; D006305:Health Status Indicators; D006801:Humans; D016013:Likelihood Functions; D016015:Logistic Models; D008913:Minority Groups / Q000706:statistics & numerical data; D011247:Pregnancy; D011264:Pregnancy Trimesters; D011295:Prenatal Care / Q000706:statistics & numerical data* / Q000639:trends; D012959:Socioeconomic Factors; D014481:United States / Q000453:epidemiology; D014600:Utilization Review