This populational study shows a significant decrease in neonatal mortality rate over the 10-year period, mainly in neonates with 28-36 weeks. Throughout the study, 60% of deaths occurred in the first 3 days after birth. Social indicators such as low maternal education and poor prenatal care, together with prematurity, perinatal asphyxia, and presence of congenital malformations, were associated with neonatal death in the State. It is interesting to note that delivery by cesarean, compared to vaginal, was protective against neonatal mortality for preterm infants at 22-31 weeks of gestational age, but it was a risk factor for those with 32-41 weeks.
Children face the highest risk of dying in their first month of life, at a global rate of 18
deaths per 1,000 live births. Globally, an estimated 2.5 million newborns died in the first month of life in 2018 – approximately 7,000 every day . This populational study shows that neonatal deaths decreased from 9.1 per thousand live births in 2004 (5,455 deaths; 15/day) to 7.4 per thousand in 2013 (4,543 deaths; 12/day) in São Paulo State. On one hand, the improvement in São Paulo State rates is noteworthy: in Latin America and Caribbean region as a whole and in Brazil in particular, the neonatal mortality decreased, respectively, from 13.1 and 14.7 per thousand live births in 2004 to 9.9 and 9.7 in 2014 . On the other hand, if we compare our numbers with those retrieved from countries with a HDI similar to São Paulo State (0.82), such as Russia (0.82) and Argentina (0.83), the neonatal mortality rate per thousand live births was, in 2018, respectively, 3,0 and 6.0 , showing that despite improvements in São Paulo, the rates are exceedingly high. This paradoxical way of looking at the results may be the consequence of a lack of equilibrium between economic indicators and health care investments. As shown for middle income countries in general, the focus of public health system during the last 20 years was mainly aimed at developing the infrastructure for inpatient care of sick newborns, but these efforts were not followed by investments in quality of care .
The major reduction in neonatal mortality rates in the study period was seen in post-term (58%), moderate preterm (52%) and term (31%) infants, and the worst performance occurred in those born with a gestational age <28 weeks (15% reduction). According to the World Health Organization, more than 80% of premature births occur between 32-36 weeks of gestation and survival is possible to almost all of them if essential care is offered, without needing intensive care interventions . In Brazil, in 2014, 86% of premature births occurred in this gestational age range , indicating a great potential to prevent the death of preterm neonates. In fact, during the study period, among all preterm live births in São Paulo State, 85% had a gestational age between 32-36 weeks and the decrease of the mortality rate was higher among them than the decrease observed in very preterm infants. Taken together with the reductions shown in the mortality rates of post-term and term infants from 2004 to 2013 and with the much smaller reduction in very preterm mortality rate in the same period, these observations suggest that essential newborn care was increasingly available throughout the State, but intensive care was either not largely available or did not have enough quality to ensure the survival of infants that required a more complex level of care. It seems that, even in the richest Brazilian State , further improvement in newborn health outcomes will depend on the ability to address the gap between coverage and quality .
In our study, the median time until 50% of deaths occurred was 3 days for all infants and for all gestational age groups, except for infants with 22-27 and ≥42 weeks of gestations, in which 50% of deaths occurred with 1.4 days after birth. Like to our results, in a systematic review of 22 studies in low- and medium-income countries, 62% of the total neonatal deaths occurred during the first 3 days of life . These findings are probably related to the suboptimal quality of care provided in health facilities. As highlighted by Sankar et al, facility-based care of neonates should be strengthened to improve the care of sick babies in the first few days of life, allocating more resources, including skilled manpower and finances, to existing facilities .
According to the “Every Newborn” action plan, three causes accounted for more than 80% of neonatal mortality worldwide in 2012: complications of prematurity, intrapartum-related neonatal deaths (including birth asphyxia) and neonatal infections . In our data, the main basic causes of death were respiratory disorders, that may be considered as a proxy for prematurity, infections, and perinatal asphyxia, with an important contribution of congenital malformations. The results indicate that São Paulo State, during the study period, faced a double challenge of dealing with neonatal deaths caused by preventable causes that prevail in medium and low-income countries, and, at the same time, dealing with deaths by congenital malformations that need a more complex level of care. Analysis of basic causes of deaths by year show that the State was able to decrease the rates associated with respiratory causes, probably in a parallel way to the large reduction of deaths in infants with 28-36 weeks of gestational age, and deaths caused by perinatal asphyxia. Deaths caused by infections and congenital malformations remained stable throughout the period. Again, the results suggest that, in São Paulo, during the study period, development of the infrastructure for inpatient care of sick newborns did occur, but investments in quality of care are still lacking .
In the multivariate analysis of variables associated with neonatal death in our populational study, aside of confirming prematurity, perinatal asphyxia and congenital malformations as risk factors, maternal schooling, prenatal visits, parity, mode of delivery and sex were independently associated to neonatal mortality. There is an established causal and strong link between mothers’ education and child mortality. Gadikou et al estimated that around 4 million fewer deaths of children under 5 years of age between 1970 and 2009 could be attributed to increased educational attainment in women of reproductive age . In the State of Rio de Janeiro, Brazil, among 1,445,342 single pregnancy live births with birthweight ≥500g and gestational age ≥22 weeks, less than 4 years of maternal education increased the chance of neonatal death in 25% . Our results, with a 20% and 11% increased death ratio associated, respectively, to maternal schooling <7 years and 8-11 years reinforce the strong association of maternal education with not only access to health care, but access to qualified health care.
A similar view may be offered on the association between prenatal care and neonatal mortality. Data from 69 low- and middle-income countries from 1990 to 2013, including 752,635 observations for neonatal mortality, show that at least one antenatal care visit was associated with a reduced probability of neonatal mortality. Pregnant women who did not attend prenatal care were on average less educated and poorer than those who attended at least one visit . In another study of 57 low- and middle-income countries, from 2005 to 2015, among 464,728 live births, there was 55% lower risk of neonatal mortality among women who had the first antenatal care visit within the first trimester . In our study, having less than 4 prenatal visits was associated to 43-45% increase incidence rate ratio of neonatal death. It is important to note that 25% of mothers of the 48,309 infants that ultimately died in the neonatal period attended less than 4 prenatal visits during the study period. In 2014 and 2015, in Brazil, lack of access to prenatal care was twice more frequent in women with less than 4 years in school and in non-whites . Variables associated to neonatal deaths highlight the social and economic inequalities prevalent in São Paulo State.
According to the World Health Organization, “when medically justified, a cesarean section can prevent maternal and perinatal mortality and morbidity. There is no evidence, however, showing the benefits of the procedure for women or infants where it is not required” . In fact, in our study, the delivery by cesarean section decreased the incidence rate ratio of neonatal deaths by 37% and 11% in infants of 22-27 and 28-31 weeks respectively, and increased this rate in more than 10% in newborns with gestational age greater than 31 weeks. On one hand, the cesarean section rate is an important global indicator for measuring access to obstetric services . On the other hand, elective delivery, even at early term, is strongly associated with neonatal morbidity and mortality . In a Brazilian study of 11,774,665 live births during 2014 to 2017, the Robson groups 1 to 4 accounted for 60% of live births and 47% of all cesarean sections, showing that health policies are needed to avoid the unnecessary cesarean sections . Our data highlight once more that, in São Paulo State, the quality of care is a bigger barrier to reducing neonatal mortality than insufficient access .
The study has some limitations. The most important one is the use of secondary data, which may contain errors in records, underreporting and absence of clinical and care variables potentially associated with neonatal death. However, the database provided by SEADE Foundation manages to relate data from the civil registry with epidemiological data originated from death and live birth certificates, producing consistent information, and minimizing these problems . Another limitation is the use of data updated until 2013, but the deterministic linkage of birth and death certificates for years 2014 on, that provide the database of our study, is still ongoing. We believe that the quality and consistency of the results presented in our study can be used to discuss time trends in neonatal mortality and its determinants and to design public policies in São Paulo State. Of course, the neonatal mortality data presented here is regional, but the discussion of causes and variables associated may be generalized to other regions and middle-income countries where economic development is not followed by social equity.
In conclusion, the study showed a significant decrease in neonatal mortality rate over the 10-year period, mainly in neonates with 28-36 weeks. Low maternal education and poor prenatal care, together with prematurity, perinatal asphyxia, and presence of congenital malformations, were associated with neonatal deaths in São Paulo State. Cesarean delivery, compared to vaginal, was protective against neonatal mortality for very preterm infants, but it was a risk factor for those with gestational age ≥32 weeks. Efforts to reduce neonatal mortality in the São Paulo State should focus on access to qualified care.