Executive Summary: Koch et al. article PLoS ONE 2012, May 4 Available in http://dx.plos.org/10.1371/journal.pone.0036613 A thorough analysis of over 50 years of excellent maternal mortality data from the nation of Chile has revealed that the most important factor in reducing maternal mortality is the educational level of women. Educating women enhances a woman’s ability to access existing health care resources and directly leads to a reduction in her risk of dying during pregnancy and childbirth. The research was conducted on behalf of the Chilean Maternal Mortality Research Initiative (CMMRI), which is an independent collaborative study conducted by researchers from the Department of Family Medicine at University of Chile; Institute of Molecular Epidemiology (MELISA) from the Center of Embryonic Medicine and Maternal Health at Universidad Católica de la Santísima Concepción (UCSC); and the Women’s Health Research Project at the University of North Carolina-Chapel Hill. The study was directed by Dr Elard Koch, epidemiologist and director of the CMMRI and professor from University of Chile and UCSC. The most controversial and important finding is that making abortion illegal in Chile did not result in an increase in maternal mortality. Chile is recognized as one of the countries with the most restrictive abortion laws in the world and has been criticized because of the purported possible deleterious consequences on maternal health. Moreover, three initiatives for legalizing abortion based on this argument were rejected last month by the Chilean parliament. In this controversial scenario, the recently published study at PLoS ONE this week, demonstrates clearly that prohibition of abortion did not increase maternal mortality and situates to Chile with one of the lowest maternal and abortion mortality rates in the world. Indeed, making abortion illegal in Chile was followed by a further reduction in maternal mortality. The authors analyzed official data from the National Institute of Statistics, from 1957-2007. They also simultaneously analyzed factors likely to influence maternal mortality, such as education years, income per capita, total fertility rate, birth order, clean water, sanitary sewer, and delivery by skilled attendants. And finally they included in their analysis pertinent educational and maternal health policies implemented in 1965, and legislation that prohibited abortion in 1989 to assess the effects of these policies on maternal mortality. Extremely accurate vital statistics and socioeconomic data available in Chile spanning the past 60 years offers a unique opportunity to evaluate each of these factors and their effect on reducing maternal mortality. Thus Chile serves as a natural experiment to investigate the effects of policy changes before and after the interventions were implemented. During the study period, overall maternal mortality ratio (MMR, the number of maternal deaths related to childbearing divided by the number of live births) dramatically declined by 93.8%, from 293.7 deaths per 100,000 live births decreasing to 18.2 deaths per 100,000 live births, making Chile a model for maternal health in the world. The factors affecting this decrease included the predictable factors of delivery by skilled attendants, clean facilities and fertility. But the most important factor, and the one which increased the effect of all other factors was the educational level of women. For every additional year of maternal education there was a corresponding decrease in the MMR of 29.3/100,000 live births. One of the most interesting and controversial findings was that contrary to what has been claimed prior to this publication, making abortion illegal did not result in an increase in maternal mortality. The highest maternal mortality rate was observed in 1961, during a time when therapeutic abortion was legal. When abortion was made illegal in 1989, the MMR decreased from 41.3 to 12.7 per 100,000 live births (-69.2%). The data from Chile clearly demonstrate that making abortion illegal does not result in an increase of deaths from abortion. On the contrary, deaths directly attributable to abortion declined dramatically after abortion was prohibited by law. Abortion deaths decreased from 95.1 per 100,000 live births in 1961 to 0.83 per 100,000 live births in 2007. This represented an accumulated reduction of 99.1% on this indicator. Moreover, the accumulated decrease on abortion mortality for the period between 1989 and 2007 was -9.95 deaths per 100,000 live births. Thus, Chile has reached one of the lowest abortion mortality rates in the world. Additional evidence was provided that the overall number of elective abortions similarly declined. This analysis of the effect of abortion legislation on maternal mortality is the first evidence-based publication in the medical literature which demonstrates the real effect of making elective abortion illegal on the health of women. The lack of correlation between high maternal mortality and prohibition of abortion observed in this study also confirms circumstantial observations made in Europe. The lowest MMRs in Europe are in countries such as Ireland, Malta and Poland, in which elective abortion is illegal. Considering Chile has one of the lowest maternal mortality rates in the world, this analysis of Chilean maternal mortality statistics provides a model for other countries seeking a successful model for decreasing maternal mortality, and provides evidence that legalization of abortion is unnecessary to decrease maternal mortality. This analysis also confirmed the consensus of the scientific community that delivery by skilled birth attendants is a key factor in reducing maternal mortality. The increase in skilled birth attendants should be one of the key strategies in improving maternal health. In Chile a decrease of -2.41 maternal deaths per 100,000 live births for each 1% increment in the number of deliveries performed by skilled attendants was observed; taking into account the parallel effect of the increasing women’s education level, a decrease of -4.58 maternal deaths per 100,000 live births for each 1% increment in the number of deliveries performed by skilled attendants was observed. This finding confirms that increasing the educational levels of mothers, other key variables are favourably influenced such as access to early prenatal control and the subsequent delivery by skilled personnel. Another key factor in decreasing maternal mortality is the accessibility of maternal healthcare services. Nutrition programs for mother and child, coupled with the distribution of fortified milk at primary care clinics created new opportunities of prenatal, prenatal and postnatal care for both mother and child. This strategy practically eradicated malnutrition, increased birth weight and contributed to the noteworthy reduction in infant mortality observed in Chile, 3.1/1000 live births for infants 28 days to 1 year of age. An interesting finding of this study was the presence of a “fertility paradox”. Although a strong correlation did exist between the decline on the MMR and the reduction on total fertility rate (i.e. the average number of children that would have been born to a woman over her reproductive lifetime), the increase in the number of first pregnancies at advanced ages was directly associated with an increase on maternal deaths. For every 1% increment in primiparous women giving birth older than 30 years of age, an increase of 30 maternal deaths per 100,000 live births was estimated. Thus, when the total fertility decreases and produces a delayed motherhood it can also provoke a deleterious effect on maternal health via an increase of the obstetric risk associated with childbearing at advanced ages. The Chilean natural experiment over the last 50 years translates into a dynamic and ongoing phenomenon of “aging pregnancy”, or “fertility paradox”, which is today and will be tomorrow’s leading cause of death for mothers. The picture for Chile includes a transition of leading causes of death. Direct causes –those directly attributable to pregnancy condition– were the rule before 1980, but from then, indirect causes –those attributable to underlying non-obstetric pre-existing chronic conditions such as hypertension, diabetes, and obesity among others– rise as the most prevalent. This is certainly a paradox: education is the major modulator that has helped Chile to reach one of the safest motherhood in the world, but also contributes to decrease fertility, delaying motherhood and puts mothers on risk because of their older age. Thus, an emergent problem nowadays, it is not a matter of how many children a mother has, but a matter of when. Legalization of abortion is not an appropriate strategy to decrease maternal deaths either. Improvements in maternal health and a dramatic decrease in maternal mortality occurred without legalization of abortion in Chile. The overall improvement is not attributable to its legal or illegal status, but to education increase of women as the major modulator of access to high quality maternal health services and reproductive behaviour. Finally, Koch et al. note that recent global estimates on maternal mortality continue to be underestimating the progress on maternal health in several Latin American countries. In a direct comparison of the MMR estimates by the World Health Organization (WHO) technical report with available full official domestic data in eight countries of the American continent in 2008, an important percent of overestimation was observed in WHO estimates for these countries (e.g. 35.4% for Colombia, 48.6% for Mexico, 57.6% for Chile and 76.3% for Argentina). Conclusions Taken together, the Chilean natural experiment over the last fifty years suggests that the progress on maternal health in developing countries is a function of the following factors: an increase in the educational level of women, complementary nutrition for pregnant women and their children in the primary care network and schools, universal access to improved maternal health facilities (early prenatal care, delivery by skilled birth attendants, postnatal care, availability of emergency obstetric units and specialized obstetric care); changes in women’s reproductive behaviour enabling them to control their own fertility; and improvements in the sanitary system ―i.e. clean water supply and sanitary sewer access. Furthermore, it is confirmed that women’s educational level appears to have an important modulating effect on other variables, especially promoting the utilization of maternal health facilities and modifying the reproductive behaviour. Consequently, it is proposed that these strategies outlined in different MDGs and implemented in different countries may act synergistically and rapidly to decrease maternal deaths in the developing world.