The study found high rates of neonatal mortality associated with asphyxia in poorer parts of the state of Sao Paulo

Researchers analyzing data from the state of Sao Paulo, Brazil, found the highest infant mortality rates from asphyxia in cities in the south, southeast and north of the state between 2004 and 2013. They crossed these results with economic data and found a combination of high mortality at low gross domestic product (GDP) per capita in 31 of the cities. Neonatal asphyxia strongly correlates with poor quality antenatal and postpartum care.

These are the main findings of a study reported in FLAT FIRST by researchers from the Federal University of Sao Paulo (UNIFESP) and the State Data Analysis System in Sao Paulo (SEADE).

The study showed that the methodology used, combining spatial analysis and secondary data, is effective in locating clusters of cases and can therefore contribute to public health planning and policy formulation.

Neonatal and infant mortality is a key indicator of a society’s overall health. Understanding its evolution by analyzing the root causes of death in this age group, as well as related geographical and demographic factors, helps politicians plan actions to achieve the UN Sustainable Development Goals (SDGs).

“It is important to analyze the data very closely in order to contribute to policy making. One way to do this is to find out where the phenomena occur. In our study, we applied the methodology to asphyxia-related neonatal mortality, providing a clarification that shows where the problem is most serious, “said Infectious Diseases Specialist Carlos Roberto Veiga Kiefer, a professor at UNIFESP School of Medicine and principal investigator with Ruth Ginsburg and Maria Fernanda Branco de Almeida.

According to the FAPESP-supported study, the number of asphyxia-related neonatal deaths (of babies aged 28 days or less) reported in the state was 6,713, out of a total of 5,949,267 live births, corresponding to 1.13 per year. 1000 live births in the analyzed period.

In the identified clusters, the percentages range from 1.1-1.5 to 1.5-3.2 per 1000 live births. “[L]due to GDP per capita associated with high municipal mortality rates associated with neonatal asphyxia, […] assuming this [their] spatial distribution […] it can be partially explained by this economic indicator “, the authors write in the article.

The first author, Daniela Testoni Costa-Nobre, also associated with UNIFESP, said other variables not analyzed in the study could correlate with this type of mortality besides GDP. “We focused on identifying areas and their relationship to the economic indicator,” she said. “The methodology can be used to analyze other factors that may also help explain neonatal mortality.”

According to Costa-Nobre, the optimized, structured and hierarchical approach used in the study allowed researchers to identify high-risk areas for neonatal asphyxia-related mortality, showing that the methodology could help policymakers find ways to reduce neonatal deaths. babies that can be avoided.

Neonatal asphyxia is caused by several factors and problems that cause a lack of oxygen or disrupt organ perfusion during pregnancy, childbirth and childbirth. It strongly correlates with poor quality antenatal and postpartum care and is considered one of the leading causes of preventable neonatal death, along with infections and premature birth.

Any complication in the mother increases the risk of prenatal asphyxia, so proper care for pregnant women, especially those at risk, is a form of prevention. Hence the importance of good antenatal care throughout pregnancy and the availability of qualified specialists during childbirth. “

Daniela Testoni Costa-Nobre, first author


The researchers conducted a population-based study using a spatial analysis by region, including all live births of mothers living in the state of Sao Paulo from 2004 to 2013, except for babies weighing less than 500 g and / or gestational age below 22 weeks, infants of unknown birth and gestational age and infants with congenital anomalies. The dataset was available between October 2018 and June 2021.

Asphyxia-related neonatal mortality is defined as any death less than 28 days after birth, with hypoxia, asphyxia or aspiration of meconium as the cause of death in any order of death.

Geoprocessing involved detecting first-order effects by quintiles (datasets divided into five equal parts) and spatial maps with a moving average, followed by detecting second-order effects based on global and local spatial autocorrelations using the Moran index, respectively. and LISA, before and after Bayesian smoothing.

The Moran index is a correlation coefficient that measures the total spatial autocorrelation of a data set. LISA stands for Local Spatial Association Indicator, a statistical parameter that can be used to identify local clusters (adjacent characteristics with similar values).

The group also applied Spearman’s correlation analysis to determine the relationship between asphyxia-related neonatal mortality and GDP per capita for municipalities with significant LISA values, identifying clusters of these deaths in the southern, southeastern, and northwestern parts of the state. .

Following local Bayesian estimates, the clusters were more pronounced and there was a partial overlap between areas with higher mortality and lower GDP per capita.

According to Kiefer, as far as the group is aware, this is the first study to show the spatial distribution of the specific cause of neonatal mortality in Brazil.

Human development

Sao Paulo is the richest state in Brazil with a GDP of about 2 trillion BRL. It is the third largest regional economy and consumer market in Latin America. There are 645 municipalities with human development index (HDI) values ​​in the range of 0.639 to 0.826.

According to the Brazilian Sustainable Development Goals (SDGs), the neonatal mortality rate in Sao Paulo was 7.44 per 1,000 live births in 2018 (the last year for which data are available), compared to the national average of 9.15. The lowest percentage was reported in the state of Santa Catarina (6.91), and the highest in the state of Amapa (15.6)more in Portuguese at:

The UN adopted 17 SDGs in 2015. SDG 3 is “Ensuring a healthy life and promoting well-being for all ages”. It calls for an end to preventable deaths of newborns and children under the age of five by 2030, with all countries aiming to reduce neonatal mortality to at least 12 per 1,000 live births.


Sao Paulo Research Foundation (FAPESP)

Reference journal:

Costa Nobre, DT, et al. (2021) Clusters of specific cause of neonatal mortality and its relationship to gross domestic product per capita: a structured spatial analytical approach. FLAT FIRST.

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