Published online April 10, 2006
PEDIATRICS
Vol. 117
No. 5
May 2006, pp.
e949-e954
(doi:10.1542/peds.2005-2354)
Reduction in Neonatal Mortality in Chile Between 1990 and 2000
Rogelio Gonzalez, MDa,
Mario Merialdi, MD, PhD, MPHb,
Ornella Lincetto, MD, MPHc,
Jeremy Lauer, MA, MScd,
Carlos Becerra, MDe,
René Castro, MDe,
Pedro García, MDe,
Ola D. Saugstad, MD, PhDf and
José Villar, MD, MPH, FRCOGb
a Department of Obstetrics and Gynecology, Sotero del Rio Hospital, Center for Perinatal Diagnosis, Catholic University of Chile, Santiago, Chile
b Departments of Reproductive Health and Research
c Making Pregnancy Safer
d Health Systems Financing, World Health Organization, Geneva, Switzerland
e Ministry of Health, Santiago, Chile
f Department of Pediatric Research, Rikshospitalet University Hospital, University of Oslo, Oslo, Norway
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ABSTRACT
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OBJECTIVE. Our objective with this article was to describe the declining trend in neonatal mortality in Chile between 1990 and 2000 and examine potential causal factors.
METHODS. Descriptive analysis of data that were provided by the Chilean Ministry of Health on all 
2900000 births occurred in Chile between 1990 and 2000. Total neonatal mortality rates (<28 days), and birth weight–specific and gestational age–specific mortality rates from 1990 to 2000 were analyzed by year. Public health interventions that were implemented during the 1990s were reviewed to assess their potential influence on the observed trends in neonatal mortality.
RESULTS. The neonatal mortality rate between 1990 and 2000 decreased from 8.3 to 5.7 per 1000 live births. This decline was not associated with decreases in the proportion of low birth weight and preterm infants but rather with declines in birth weight–specific and gestational age–specific mortality rates. Examination of the trends in birth weight–specific and gestational age–specific mortality rates showed that a marked proportional decrease in mortality rates was achieved among infants who weighed <1500 g and were delivered before 32 weeks. It is plausible, both biologically and temporally, that the observed trends in the reduction in birth weight–specific and gestational age–specific mortality rates are associated with the introduction of specific sector-wide interventions that aim to improve newborn care in very preterm and low birth weight infants.
CONCLUSIONS. Important reductions in newborn mortality in developing countries are possible with the implementation of effective neonatal care interventions.
Key Words: health policy • public health • neonatal mortality • international child health • health services
Abbreviations: LBW—low birth weight • VLBW—very low birth weight
Newborn health is 1 of the most striking examples of health inequality in the world. As many as 99% of the 4 million neonatal deaths that occur each year take place in the poorest countries of the world.1 This is double the deaths that are caused by HIV/AIDS.1 These figures become even more worrisome when one considers that for every early neonatal death, 1 stillbirth also occurs,1 making perinatal deaths responsible for 7% of the total global burden of disease.2 This proportion exceeds that caused by vaccine-preventable diseases and malaria together.3 The disparity between rich and poor countries in neonatal mortality is unacceptably large and continues to increase.4
The reduction of child mortality has been included among the Millennium Development Goals that the United Nations has set to be attained by year 2015.5 Despite the decline witnessed in mortality rates among children who are younger than 5 years in the past few decades, neonatal mortality rates have not changed substantially and now represent 38% of all deaths of children who are younger than 5 years.1 It is estimated that as child mortality rates will continue to decrease as a result of the implementation of effective interventions such as vaccines and oral rehydration therapy, the proportion of neonatal deaths will increase.3
Deaths of infants that are associated with childbirth in developing countries are most unjust. Pregnancy and childbirth are not diseases, and they should have a positive outcome. This is the norm in developed countries, but it is not true for most developing countries, where women and their infants still die in large numbers. Chile presents a positive example of a developing country that has managed, arguably by implementing a suite of effective perinatal interventions, to reduce neonatal mortality rates considerably between 1990 and 2000.6,7
In this article, we present trends in neonatal mortality in Chile between 1990 and 2000 and examine them to determine what has been the impact on neonatal mortality of changes in birth weight–specific and gestational age–specific mortality rates. In the absence of data on causes of death, this analysis could only suggest which newborn subpopulations were most likely to benefit from the public health interventions that were implemented by the Chilean Ministry of Health in the 1990s and, moreover, which pathologies might have been prevented or treated by those interventions. This analysis provides insights that may be helpful for other countries and international agencies for developing public health policies to contribute to the achievement of the Millennium Developmental Goals.
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METHODS
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A national database from the Chilean Ministry of Health of Chile, Department of Statistics, was used for analysis. Overall neonatal mortality and birth weight–specific and gestational age–specific neonatal mortality rates for every year from 1990 to 2000 were calculated. In addition, we obtained data on the distributions of birth weight and gestational age at delivery for the same years. The data set of the Ministry of Health includes all of the 250000 deliveries per year in Chile. A list of all of the sector-wide public health activities that were implemented by the Ministry of Health in the 1990s with a potential impact on newborn health also was obtained, as well as data on maternal mortality ratio, per capita income, and annual expenditure in the public health sector. The Chilean NICU system includes 28 NICUs throughout the country. The national health system comprises 26 regions, each of them with at least 1 regional hospital with a NICU. NICUs are similar in equipment and standards of care. In 1991, a national committee that included the most preeminent Chilean neonatologists set the standards for equipment and training of staff who operate in the NICUs. In each NICU, there are 3 levels of care that provide increasingly specialized assistance. Reorganization of the NICUs happened at the same time in the whole country, and there was no change in the number of NICUs in the decade 1991–2000. In 1994, a policy for neonatal cardiopulmonary resuscitation was implemented at the national level. In addition, in the same year, the 7 NICUs in the Santiago metropolitan area were equipped with cardiorespiratory monitors.
In Chile, >99% of the total number of births occur in an institution under skilled care (doctor or midwife). Approximately 68% of total births occur in the main regional hospitals with NICUs. Women with high-risk pregnancy, preterm labor, and prenatal diagnosis of intrauterine growth restriction are delivered at the hospitals with NICUs. A protocol has been implemented at the national level to regulate the referral of neonates who are born in hospitals without a NICU to the regional hospitals. There also are standardized protocols for the treatment of newborns who weigh <1500 g and for cases of respiratory distress syndrome.
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RESULTS
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Table 1 presents neonatal and infant mortality rates (deaths per 1000 live births); maternal mortality ratio (per 100000 live births); and percentages of prematurity (<32 and <37 weeks' gestational age), low birth weight (LBW; birth weight <2500 g), and very low birth weight (VLBW; birth weight <1500 g) for the decade 1990–2000. There is an evident declining trend in mortality rates. However, rates of prematurity, LBW, and VLBW tended to remain stable. The percentage of newborns who were delivered under 37 weeks' gestational age increased only slightly.
To investigate whether the observed trends in neonatal mortality were affected by changes in birth weight–specific and gestational age–specific mortality rates, we displayed mortality rates by birth weight intervals and by week increments in gestational age at delivery for each year as shown in Tables 2 and 3, respectively. In addition, the tables present year-to-year and 1990–2000 percentage changes. Although we observed a reduction in mortality in all birth weight and gestational age categories, the largest reduction in proportional terms was seen in the lowest birth weight and gestational age categories (<1500 g and <32 weeks). By looking at the percentage year-to-year changes, the decreasing trends tend to show more noticeable drops after 1991, 1994, and 1998, especially among the lowest birth weight categories, suggesting that the interventions that were implemented in those years (respectively, new equipment, training in cardiorespiratory resuscitation, and introduction of surfactant therapy at the national level) might have had an important effect on the prevention or treatment of pathologies that are responsible for neonatal mortality in LBW infants. Table 4 presents a summary of the most important newborn care interventions that were implemented by the Ministry of Health, Chile, between 1990 and 2000.
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TABLE 3 Gestational Age at Delivery-Specific Neonatal Mortality Rates (<28 Days) and Year-to-Year Percent Changes: Chile, 1990–2000
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DISCUSSION
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We examined data on all deliveries in Chile between 1990 and 2000 (2900000 deliveries) to describe changes in neonatal mortality rates and their possible causal factors. Because the percentages of LBW and preterm delivery did not change significantly during the decade, it is likely that the observed reduction in mortality was attributable to declines in birth weight–specific and gestational age–specific mortality rates. This is similar to what was reported previously in other studies.8 The authors of a study that was based on perinatal data from New York City were able to examine in more detail a similar trend and to relate it with birth weight–specific mortality rates and causes of death.9 The authors of that study observed that the decline in neonatal mortality that was observed in New York City between 1988 and 1991 was not associated with a change in the birth weight distribution during the same years. When comparing unadjusted and birth weight–adjusted mortality rates, they could show that the reduction in neonatal mortality was attributable mainly to a decline in birth weight–specific mortality rates. The authors suggested that this pattern is more likely to be associated with causal factors and interventions that act perinatally or postnatally rather than earlier in pregnancy, among them, improved and easier access to medical care and use of preventive strategies.9 Most of the activities that were implemented by the Ministry of Health in Chile in the decade of the 1990s fit those categories, and it is plausible that they played a role in the decline in neonatal mortality that was observed between 1990 and 2000.
From an analysis of the causes of deaths, Kalter and O'Campo9 could show the introduction of surfactant as an important factor in preventing deaths from respiratory distress syndrome among preterm infants. The data set from Chile does not provide information on causes of death. However, we observed a decline in some birth weight–specific (<1500 g) and gestational age–specific (<32 weeks) mortality rates between 1997 and 2000. This observation allows one to hypothesize a potential causal association. As surfactant therapy was introduced in Chile at the national level in 1998, these data provide some indication of the effectiveness of this public health intervention implemented at the national level in decreasing mortality in specific newborn subgroups.
The potential effect of the surfactant policy is both temporally and scientifically plausible. The data show a decline in mortality in the subgroups of neonates who were likely to benefit more from surfactant therapy after the implementation of that strategy in 1998. It could be argued that modifications in other practices, such as administration of prenatal corticosteroids, could have affected mortality rates in the same newborn subgroups. To address this issue, we examined data that were collected at the Sotero del Rio Hospital in Santiago, Chile (10000 deliveries per year), that showed that the percentage of surviving neonates whose birth weight was <1500 g and who received a course of steroids prenatally remained stable during the period from 1997 to 2000 (84.8% and 82.7%, respectively; E. Pitaluga, MD, A. Alegria, MD, E. Jimenez, MD, P. Mena, MD, unpublished data, 2000). Although we could not retrieve similar data at the national level, because of the strong focus on uniform nationwide implementation of health policies that characterizes the Chilean health care system, we are not inclined to think that other hospitals changed their practices in relation to prenatal corticosteroid administration in the years 1997–2000.
The data presented in this article are, to our knowledge, the first indication of effectiveness of the introduction of a policy for widespread use of surfactant at the national level. From our data, it was more difficult to associate other specific interventions with decline in neonatal mortality. Because those interventions likely benefit a wider range of birth weight and gestational age categories, it is more difficult to draw conclusions on potential causal associations from our data. Nevertheless, it is worthwhile to notice the decline in birth weight–and gestational age–specific mortality rates for VLBW and early preterm infants after 1991 and 1994. Those were the years when equipment in the NICUs was renewed at the national level, when each unit was staffed with neonatologists (1991), and when a policy for neonatal cardiopulmonary resuscitation training was implemented at the national level (1994). In addition, in 1994, all NICUs in the Santiago metropolitan area were equipped with cardiorespiratory monitors. All of these interventions plausibly played a role in decreasing birth weight–specific and gestational age–specific mortality rates, although they might have acted on several birth weight and gestational age categories and prevented several causes of deaths. This consideration points to the main limitation of our study, which is the lack of data on causes of deaths, a limitation that could be only partially overcome by the examination of changes in birth weight–specific and gestational age–specific mortality rates.
Importantly, in considering the improvements in newborn health achieved by Chile in the 1990s, it is critical to take into account that those years saw a diminution of poverty rates of 50% after a progressive increase in per capita income, a significant increase in the level of mothers' education, and a 3-fold increase in expenditures in the public health sector.10 Another indication of the improvement in health care provision during the decade 1990-2000 is the observed 40% reduction in maternal mortality ratio (a commonly used indicator of health service performance), as shown in Table 1. Although our data did not allow for an adequate analysis of the correlation between poverty reduction and improved newborn health, those observations suggest that a more detailed analysis of the interaction between socioeconomic changes and specific public health policies is warranted. In addition, it would be important to estimate the costs in terms of health expenditure related to the implementation of the interventions that likely contributed to the observed decline in neonatal mortality. We are collecting the data to perform this analysis, which will be presented in a separate article. Although an indication of the costs that are associated with improvements in newborn health will be critical to assess the feasibility of implementing similar interventions in other low-resource countries, the experience of Chile suggests that substantial improvements in neonatal survival are within the reach of countries with resource constraints. At our level of analysis, the results suggests that political will, expressed by increased public expenditure in the health sectors, formulation of specific health policies, and implementation of interventions that have been shown to be effective can have important results in decreasing the gap in newborn health between the developed and the developing world.
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ACKNOWLEDGMENTS
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We acknowledge the help that we received from Dr Jorge Torres Pereira (University of Chile), who collaborated with us by providing valuable information.
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FOOTNOTES
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Accepted Nov 28, 2005.
Address correspondence to Rogelio Gonzalez, MD, Department of Obstetrics and Gynecology, Sotero del Rio Hospital, Center for Perinatal Diagnosis, Catholic University of Chile, Av Concha y Toro 3459, Puente Alto Santiago, Chile. E-mail: roggonza{at}med.puc.cl
The views expressed in this article are solely the responsibility of the authors and do not necessarily represent the views of the World Health Organization or the Chilean Ministry of Health.
The authors have indicated they have no financial relationships relevant to this article to disclose.
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PEDIATRICS (ISSN 1098-4275). ©2006 by the American Academy of Pediatrics
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