title: National, regional, and global rates and trends in contraceptive prevalence and unmet need for family planning between 1990 and 2015: a systematic and comprehensive analysis.
abstract: BACKGROUND
  Expansion of access to contraception and reduction of unmet need for family planning are key components to improve reproductive health, but scarce data and variability in data sources create difficulties in monitoring of progress for these outcomes. We estimated and projected indicators of contraceptive prevalence and unmet need for family planning from 1990 to 2015.
  
  
  METHODS
  We obtained data from nationally representative surveys, for women aged 15-49 years who were married or in a union. Estimates were based on 930 observations of contraceptive prevalence between 1950 and 2011 from 194 countries or areas, and 306 observations of unmet need for family planning from 111 countries or areas. We used a Bayesian hierarchical model combined with country-specific time trends to yield estimates of these indicators and uncertainty assessments. The model accounted for differences by data source, sample population, and contraceptive methods included in the measure.
  
  
  RESULTS
  Worldwide, contraceptive prevalence increased from 54·8% (95% uncertainty interval 52·3-57·1) in 1990, to 63·3% (60·4-66·0) in 2010, and unmet need for family planning decreased from 15·4% (14·1-16·9) in 1990, to 12·3% (10·9-13·9) in 2010. Almost all subregions, except for those where contraceptive prevalence was already high in 1990, had an increase in contraceptive prevalence and a decrease in unmet need for family planning between 1990 and 2010, although the pace of change over time varied between countries and subregions. In 2010, 146 million (130-166 million) women worldwide aged 15-49 years who were married or in a union had an unmet need for family planning. The absolute number of married women who either use contraception or who have an unmet need for family planning is projected to grow from 900 million (876-922 million) in 2010 to 962 million (927-992 million) in 2015, and will increase in most developing countries.
  
  
  CONCLUSIONS
  Trends in contraceptive prevalence and unmet need for family planning, and the projected growth in the number of potential contraceptive users indicate that increased investment is necessary to meet demand for contraceptive methods and improve reproductive health worldwide.
  
  
  BACKGROUND
  United Nations Population Division and National University of Singapore.
authors.affiliation: Department of Statistics and Applied Probability and the Saw Swee Hock School of Public Health, National University of Singapore, Singapore.
authors.forename: Leontine
authors.initials: L
authors.lastname: Alkema
authors.forename: Vladimira
authors.initials: V
authors.lastname: Kantorova
authors.forename: Clare
authors.initials: C
authors.lastname: Menozzi
authors.forename: Ann
authors.initials: A
authors.lastname: Biddlecom
mesh_terms: D000293:Adolescent; D000328:Adult; D001499:Bayes Theorem; D003268:Contraception Behavior / Q000639:trends*; D005193:Family Planning Services / Q000639:trends*; D005260:Female; D014943:Global Health; D006297:Health Services Accessibility; D006301:Health Services Needs and Demand / Q000639:trends*; D006801:Humans; D008390:Markov Chains; D008875:Middle Aged; D009010:Monte Carlo Method