Epidemiology & Public Health
Natural experiments
¿What are natural experiments?

These investigations study the impact of a variable in the community where the epidemiologist or researcher has no control over the variables studied, nor over the populations exposed or not exposed to a certain risk factor or protective factor.
A "natural population experiment" design is used when it is not possible to experiment directly with the population, as is the case with public policies or factors to which groups or entire populations are globally exposed.

DETERMINANTS OF MATERNAL MORTALITY IN MEXICO
This report presents, as a summary for the public, the scientific evidence obtained from a thorough investigation of the determinants of maternal mortality conducted in each Mexican state. The full study was published in British Medical Journal Open (BMJ Open) and coordinated by MELISA Institute in cooperation with an international team of specialists from different institutions, such as UNAM, Duke University, the University of Utah, and the University of North Carolina-Chapel Hill.
DETERMINANTS OF MATERNAL MORTALITY IN CHILE
The aim of this study was to assess the main factors related to maternal mortality reduction in large time series available in Chile in the context of the United Nations' Millennium Development Goals (MDGs).
Increasing education level appears to favorably impact the downward trend in maternal mortality, modulating other key factors such as access and utilization of maternal health facilities, changes in women's reproductive behavior, and improvements of the sanitary system. Consequently, different MDGs can act synergistically to improve maternal health. The reduction in maternal mortality is not related to the legal status of abortion.


THE PHENOMENON OF MATERNITY AGING
In Chile, we are evaluating the postponement of maternity in primiparous women and their relationship with public health policies applied in this country in the 1960s. This study seeks to feature the first entry into motherhood throughout sixty (60) years of uninterrupted vital records. Because of its importance in maternal health, a research grant was awarded from the National Fund for Research (FONIS-CONICYT) and also an international academic collaboration.
QUALITY OF MATERNAL MORTALITY REGISTRY IN ARGENTINA
Another study, conducted by our Director (Elard S. Koch, PhD) and in collaboration with local researchers, evaluates the quality of the maternal mortality registry in Argentina for the pursuit of natural population experiments in the last 40 years. Based on the international coding of diseases (ICD), we are assessing the sensitivity of the registry to detect changes in specific groups of causes of maternal deaths in the face of an epidemic, as well as the identification of predictive factors of maternal death, using multiple and advanced statistical techniques.


IMPACT OF PANDEMIC VIRUSES IN ARGENTINE MATERNAL MORTALITY
A study led by Dr. Elard Koch, and conducted together with a team of researchers affiliated with academic centers in Argentina, Peru and Chile, used a 38-year time series of Argentine vital records to assess the trend of the maternal mortality ratio (the ratio between the number of maternal deaths and live births at the national level multiplied by 100.000 each year) for specific causes before, during and after the global outbreak caused by the pandemic H1N1 influenza virus in 2009. The full study was published in The Lancet Regional Health - Americas.