title: Women's education level, maternal health facilities, abortion legislation and maternal deaths: a natural experiment in Chile from 1957 to 2007.
abstract: BACKGROUND
  The aim of this study was to assess the main factors related to maternal mortality reduction in large time series available in Chile in context of the United Nations' Millennium Development Goals (MDGs).
  
  
  METHODS
  Time series of maternal mortality ratio (MMR) from official data (National Institute of Statistics, 1957-2007) along with parallel time series of education years, income per capita, fertility rate (TFR), birth order, clean water, sanitary sewer, and delivery by skilled attendants were analysed using autoregressive models (ARIMA). Historical changes on the mortality trend including the effect of different educational and maternal health policies implemented in 1965, and legislation that prohibited abortion in 1989 were assessed utilizing segmented regression techniques.
  
  
  RESULTS
  During the 50-year study period, the MMR decreased from 293.7 to 18.2/100,000 live births, a decrease of 93.8%. Women's education level modulated the effects of TFR, birth order, delivery by skilled attendants, clean water, and sanitary sewer access. In the fully adjusted model, for every additional year of maternal education there was a corresponding decrease in the MMR of 29.3/100,000 live births. A rapid phase of decline between 1965 and 1981 (-13.29/100,000 live births each year) and a slow phase between 1981 and 2007 (-1.59/100,000 live births each year) were identified. After abortion was prohibited, the MMR decreased from 41.3 to 12.7 per 100,000 live births (-69.2%). The slope of the MMR did not appear to be altered by the change in abortion law.
  
  
  CONCLUSIONS
  Increasing education level appears to favourably impact the downward trend in the MMR, modulating other key factors such as access and utilization of maternal health facilities, changes in women's reproductive behaviour and improvements of the sanitary system. Consequently, different MDGs can act synergistically to improve maternal health. The reduction in the MMR is not related to the legal status of abortion.
authors.affiliation: Institute of Molecular Epidemiology (MELISA), Center of Embryonic Medicine and Maternal Health, Faculty of Medicine, Universidad Católica de la Santísima Concepción, Concepción, Chile. elardkoch@gmail.com
authors.forename: Elard
authors.initials: E
authors.lastname: Koch
authors.forename: John
authors.initials: J
authors.lastname: Thorp
authors.forename: Miguel
authors.initials: M
authors.lastname: Bravo
authors.forename: Sebastián
authors.initials: S
authors.lastname: Gatica
authors.forename: Camila X
authors.initials: CX
authors.lastname: Romero
authors.forename: Hernán
authors.initials: H
authors.lastname: Aguilera
authors.forename: Ivonne
authors.initials: I
authors.lastname: Ahlers
mesh_terms: D000028:Abortion, Induced / Q000331:legislation & jurisprudence*; D000293:Adolescent; D000328:Adult; D002677:Chile / Q000453:epidemiology; D004522:Educational Status; D005260:Female; D006801:Humans; D008427:Maternal Health Services / Q000706:statistics & numerical data*; D008428:Maternal Mortality / Q000639:trends*; D008875:Middle Aged; D015233:Models, Statistical; D011247:Pregnancy; D012044:Regression Analysis; D013997:Time Factors; D055815:Young Adult