Infant mortality in three population-based cohorts in Southern Brazil: trends and differentials

Risk factors related to preventable infant mortality in Espirito Santo, Brazil

Objective

To analyse the factors associated with preventable of infant mortality, in Espirito Santo, Brazil.

Methods

Data were collected from records of notifiable of infant death of the Mortality Information System. A total of 5,089 infant deaths were classified as preventable and non-preventable according to the International Collaborative Effort on Infant Mortality (ICE) and the State System of Data Analysis Foundation (SEADE) methods. To investigate the factors associated with preventable of deaths, it was applied the logistic regression.

Results

Approximately, 73% of the deaths were preventable according to the ICE, while 76% were preventable according to the SEADE method. Using to both methods, it was observed that preterm birth, postneonatal death and birth weight between 3000 and above 4,000 g represented higher chances for preventable infant deaths. Furthermore, the medical care was more likely to preventable infant death only for ICE method.

Conclusions

The factors related to the quality of care offered in the prenatal, prepartum and childbirth periods were more relevant for the occurrence of preventable infant death. Accordingly, it is recommended to strengthen mother-child care to detect risk pregnancies during prenatal care, as well as a hierarchical, regionalized and integrated perinatal network.

Effects of responsive caregiving and learning opportunities during pre-school ages on the association of early adversities and adolescent human capital: an analysis of birth cohorts in two middle-income countries

BACKGROUND

Millions of children globally are at risk of not reaching their developmental potential because of early adversities. We hypothesised that responsive caregiving and learning opportunities, components of nurturing care, at pre-school ages might mitigate the effects of adversities.

METHODS

We analysed longitudinal birth cohort data from Brazil (1993 Pelotas Birth Cohort, n=632) and South Africa (Birth to Twenty Plus [Bt20+] Birth Cohort, n=1130) to assess whether responsive caregiving and learning opportunities at pre-school ages (2-4 years) modified associations between cumulative early adversities and adolescent human capital. The cumulative adversities score (range 0-9) included household wealth and crowding; mothers' schooling, height, age, and mental health; and children's birthweight, gestational age, and length at age 12 months. We extracted data on responsive caregiving and learning opportunities from the Early Childhood Home Observation for Measurement of the Environment inventory, assessed at age 4 years (1993 Pelotas cohort) and 2 years (Bt20+ cohort). We examined three human capital indicators: intelligence quotient (IQ) assessed at age 18 years (1993 Pelotas cohort) and 16 years (Bt20+ cohort); psychosocial adjustment assessed at age 15 years and 14 years, respectively; and height assessed at age 18 years and 16 years, respectively. We used linear models with interaction terms between cumulative adversities, and responsive caregiving and learning opportunities, to predict adolescent human capital.

FINDINGS

For each additional Z score of total cumulative adversity, adolescent IQ decreased by 5·89 (95% CI -7·29 to -4·50) points in the 1993 Pelotas cohort (p<0·0001) and 2·69 (-4·52 to -0·86) points in the Bt20+ cohort (p=0·0039). After adjusting for total cumulative adversities, adolescent IQ points increased by 5·47 (95% CI 4·20 to 6·74) with each additional Z score of learning opportunities and by 2·26 (0·93 to 3·59) with each additional Z score of responsive caregiving in the 1993 Pelotas cohort, but not in the Bt20+ cohort (0·86 [-0·12 to 1·83] and 0·65 [-0·32 to 1·61], respectively). Associations between early adversities and IQ were modified by learning opportunities in the 1993 Pelotas cohort (beta coefficient for interaction 1·74, 95% CI 0·43 to 3·04; p=0·0092) and by responsive caregiving in the Bt20+ cohort (2·24, 0·94 to 3·54; p=0·0075). High nurturing environment attenuated the negative effects of early cumulative adversities on IQ.

INTERPRETATION

Early nurturing home environments protect young children against effects of early adversities on adolescent IQ, with long-term positive associations on adolescent cognition in two middle-income countries.

FUNDING

Bill & Melinda Gates Foundation.

Changes in Infant and Neonatal Mortality and Associated Factors in Eight Cohorts from Three Brazilian Cities

Stillbirth (SBR), perinatal (PMR), neonatal (NMR) and infant mortality rates (IMR) are declining in Brazil and the factors associated with these falls are still being investigated. The objective of the present study was to assess changes in SBR, PMR, NMR and IMR over time and to determine the factors associated with changes in NMR and IMR in eight Brazilian cohorts. All cohorts are population-based (Ribeirão Preto in 1978/79, 1994 and 2010; Pelotas in 1982, 1993 and 2004; and São Luís in 1997/98 and 2010). Were included data on 41440 children. All indicators were decreased, except in the city of Pelotas, from 1993 to 2004, and except SBR in São Luís. Sociodemographic variables seem to be able to explain reductions of NMR and IMR in Ribeirão Preto, from 1978/79 to 1994, and in São Luís. In Ribeirão Preto, from 1994 to 2010 declines in NMR and IMR seem to be explained by reductions in intrauterine growth restriction (IUGR). Newborn’s gestational age had diminished in all cohorts, preventing even greater reductions of NMR and IMR. Improved sociodemographic variables and reduction of IUGR, seem to be able to explain part of the decrease observed. NMR and IMR could have been reduced even more, were it not for the worsening in gestational age distribution.

Administrative Data Linkage in Brazil: Potentials for Health Technology Assessment

Health technology assessment (HTA) is the systematic evaluation of the properties and impacts of health technologies and interventions. In this article, we presented a discussion of HTA and its evolution in Brazil, as well as a description of secondary data sources available in Brazil with potential applications to generate evidence for HTA and policy decisions. Furthermore, we highlighted record linkage, ongoing record linkage initiatives in Brazil, and the main linkage tools developed and/or used in Brazilian data. Finally, we discussed the challenges and opportunities of using secondary data for research in the Brazilian context. In conclusion, we emphasized the availability of high quality data and an open, modern attitude toward the use of data for research and policy. This is supported by a rigorous but enabling legal framework that will allow the conduct of large-scale observational studies to evaluate clinical, economical, and social impacts of health technologies and social policies.

[Basic sanitation and inequalities in color/race in urban households with under-five children, with a focus on the indigenous population]

This study aimed to analyze the presence of basic sanitation services in households with children under five years of age located in urban areas of Brazil, with a focus on indigenous children. This cross-sectional study was based on data from the 2010 Population Census. We calculated the rates of households with running water (public system), sewage disposal (public system or septic tanks), and garbage collection (directly or via public dumpsters). Multiple logistic regression (MLR) models were used to estimate associations between color/race and presence of sanitation services, based on odds ratios (OR). The study considered Brazil's urban metropolitan areas and stratified the results by major geographic region. Significance was set at 5%. The lowest frequencies were for sewage disposal, and all the rates were lower for indigenous people. MLR analyses included 29 comparisons (48.3%) in which households with indigenous children (compared to other color/race categories) were at a disadvantage, especially in the South of Brazil, where all comparisons were negative for indigenous households. Similar results appeared in metropolitan areas. The results thus suggest inequalities basic sanitation services based on color/race, where indigenous people are generally at a disadvantage, especially in the South of Brazil. Given the relationship between sanitation and health, as already demonstrated in the literature, these results can partly explain the low health levels in indigenous children in Brazil.

Stillbirth, newborn and infant mortality: trends and inequalities in four population-based birth cohorts in Pelotas, Brazil, 1982-2015

BACKGROUND

Infant-mortality rates have been declining in many low- and middle-income countries, including Brazil. Information on causes of death and on socio-economic inequalities is scarce.

METHODS

Four birth cohorts were carried out in the city of Pelotas in 1982, 1993, 2004 and 2015, each including all hospital births in the calendar year. Surveillance in hospitals and vital registries, accompanied by interviews with doctors and families, detected fetal and infant deaths and ascertained their causes. Late-fetal (stillbirth)-, neonatal- and post-neonatal-death rates were calculated.

RESULTS

All-cause and cause-specific death rates were reduced. During the study period, stillbirths fell by 47.8% (from 16.1 to 8.4 per 1000), neonatal mortality by 57.0% (from 20.1 to 8.7) and infant mortality by 62.0% (from 36.4 to 13.8). Perinatal causes were the leading causes of death in the four cohorts; deaths due to infectious diseases showed the largest reductions, with diarrhoea causing 25 deaths in 1982 and none in 2015. Late-fetal-, neonatal- and infant-mortality rates were higher for children born to Brown or Black women and to low-income women. Absolute socio-economic inequalities based on income-expressed in deaths per 1000 births-were reduced over time but relative inequalities-expressed as ratios of mortality rates-tended to remain stable.

CONCLUSION

The observed improvements are likely due to progress in social determinants of health and expansion of health care. In spite of progress, current levels remain substantially greater than those observed in high-income countries, and social and ethnic inequalities persist.

Infant mortality by color or race from Rondônia, Brazilian Amazon

OBJECTIVE

To analyze the quality of records for live births and infant deaths and to estimate the infant mortality rate for skin color or race, in order to explore possible racial inequalities in health.

METHODS

Descriptive study that analyzed the quality of records of the Live Births Information System and Mortality Information System in Rondônia, Brazilian Amazonian, between 2006-2009. The infant mortality rates were estimated for skin color or race with the direct method and corrected by: (1) proportional distribution of deaths with missing data related to skin color or race; and (2) application of correction factors. We also calculated proportional mortality by causes and age groups.

RESULTS

The capture of live births and deaths improved in relation to 2006-2007, which required lower correction factors to estimate infant mortality rate. The risk of death of indigenous infant (31.3/1,000 live births) was higher than that noted for the other skin color or race groups, exceeding by 60% the infant mortality rate in Rondônia (19.9/1,000 live births). Black children had the highest neonatal infant mortality rate, while the indigenous had the highest post-neonatal infant mortality rate. Among the indigenous deaths, 15.2% were due to ill-defined causes, while the other groups did not exceed 5.4%. The proportional infant mortality due to infectious and parasitic diseases was higher among indigenous children (12.1%), while among black children it occurred due to external causes (8.7%).

CONCLUSIONS

Expressive inequalities in infant mortality were noted between skin color or race categories, more unfavorable for indigenous infants. Correction factors proposed in the literature lack to consider differences in underreporting of deaths for skin color or race. The specific correction among the color or race categories would likely result in exacerbation of the observed inequalities.

Providers' compliance with practice guidelines of prenatal and neonatal care to reduce neonatal mortality: 2004 versus 2012

Objective:

To evaluate providers' compliance with practice guidelines of prenatal and neonatal care in order to reduce neonatal mortality.

Methods:

Uncontrolled before-and-after study designed to evaluate changes that occurred between 2004 and 2012, after the interventions proposed by the Municipality Committee of Research on Child Deaths, Foetal and Maternal Death (COMAI) on the frequency of the process indicators for perinatal assistance improvement. A total of 254 patients were studied in 2004 and 259 patients in 2012.

Results:

During the study period, there was an increase of 65% in the use of prenatal corticosteroids among pregnant women in preterm labor with gestational age of ≤ 34 weeks (rate of use of 38.0 and 62.8% in 2004 and 2012, respectively; p < 0.001), 35% of increase in the use of surfactant among newborns with ≤ 34 weeks of gestational age (41.3 and 55.6% in 2004 and 2012, respectively; p = 0.025) and a reduction of 16% in the prevalence of hypothermia (70.8 and 59.4% in 2004 and 2012, respectively; p = 0.009) at the neonatal intensive care unit admission.

Conclusions:

Prenatal and neonatal care practices improved between 2004 and 2012. At the end of the study period, rates of use of antenatal steroids and surfactant were lower than figures reported internationally. Similarly, the frequency of hypothermia at the neonatal intensive care unit admission was higher than the occurrence observed in developed countries.

Changes in perinatal health in two birth cohorts (1997/1998 and 2010) in São Luís, Maranhão State, Brazil

The objective of this study was to analyze changes in perinatal health in two birth cohorts started in 1997/1998 and 2010, respectively, in São Luís, Maranhão State, Brazil. A total of 2,493 live born infants were included in 1997/1998 and 5,166 in 2010. Low birth weight (LBW) rate did not change (8.5% in 1997/1998 and 8.6% in 2010). Preterm birth (PTB) rate also remained stable (13.2% in 1997/1998 and 13% in 2010). Teenage deliveries and births to single mothers decreased. Maternal schooling and prenatal care coverage increased. Intrauterine growth restriction (IUGR) decreased from 13.3% to 10.6% (p < 0.001). The perinatal mortality rate decreased from 36.6 to 20.7 per 1,000 (p < 0.001) and the infant mortality rate (IMR) dropped from 28.5 to 12.8 per 1,000 (p < 0.001). The cesarean rate increased from 34.1% to 47.5% (p < 0.001). In conclusion, despite favorable changes in socio-demographic, behavioral, and health service factors and decreasing rates of IUGR and perinatal and infant mortality, LBW and PTB remained stable, while the cesarean rate increased.

Óbitos infantis evitáveis nas coortes de nascimentos de Pelotas, Rio Grandedo Sul, Brasil, de 1993 e 2004

Comparou-se a mortalidade infantil por causas evitáveis (óbitos reduzíveis por ações de imunoprevenção; por adequada atenção à mulher na gestação e parto e ao recém-nascido; por ações adequadas de diagnóstico e tratamento; e por ações adequadas de promoção à saúde vinculadas às ações adequadas de atenção à saúde) nas coortes de nascimentos de Pelotas, Rio Grande do Sul, Brasil, de 1993 e 2004. Os óbitos foram monitorizados mediante visitas aos hospitais, cartórios, cemitérios, Delegacia Regional de Saúde e rastreio à base de dados do Sistema de Informações sobre Mortalidade (SIM) do Rio Grande do Sul. Na coorte de 1993, houve 5.249 nascidos vivos e 111 óbitos infantis; na de 2004, 4.231 nascidos vivos e 82 óbitos infantis. O coeficiente de mortalidade infantil evitável foi 15,2:1.000 nascidos vivos em 1993 e 15,4 em 2004. Os coeficientes de mortalidades neonatal e pós-neonatal evitáveis foram, respectivamente, 11,2 e 4,0 em 1993 e 10,9 e 4,5 em 2004. Estratégias que visem à prevenção da prematuridade poderão ajudar a reduzir a mortalidade infantil em nosso meio.

The burden of unintended pregnancies in Brazil: a social and public health system cost analysis

Background

Unintended pregnancy (UP) is an unmet medical need with consequences worldwide. We evaluate the costs of UP based on pregnancies in Brazil from for the year 2010.

Methods

The consequences of UP were evaluated using decision analysis based on pregnancy rates and outcomes as miscarriage, induced abortion, and live birth, which were factored into the analysis. The model discriminated between maternal and child outcomes and accounted for costs (in Brazilian currency [Real$, R$]) within the Brazilian public health service attributed to preterm birth, neonatal admission, cerebral palsy, and neonatal and maternal mortality. Event probabilities were obtained from local resources.

Results

We estimate that 1.8 million UPs resulted in 159,151 miscarriages, 48,769 induced abortions, 1.58 million live births, and 312 maternal deaths, including ten (3%) attributed to unsafe abortions. The total estimated costs attributed to UP are R$4.1 billion annually, including R$32 million (0.8%) and R$4.07 billion (99.2%) attributed to miscarriages and births and complications, respectively. Direct birth costs accounted for approximately R$1.22 billion (30.0%), with labor and delivery responsible for most costs (R$988 million; 24.3%) for the year 2010. The remainder of costs were for infant complications (R$2.84 billion; 72.3%) with hospital readmission during the first year accounting for approximately R$2.15 billion (52.9%). Based on the national cost, we estimate the cost per UP to be R$2,293.

Conclusion

Despite weaknesses in precise estimates in annual pregnancies and induced abortions, our estimates reflect the costs of UP for different pregnancy outcomes. The main costs associated with UP are in those carried to parturition. The health cost of abortion represents a small proportion of total costs as these are paid for outside of the public health system. Consequently, reductions in UP will generate not only cost savings, but reductions in woman and child morbidity and mortality.

Flour fortification with iron has no impact on anaemia in urban Brazilian children

Objective

To verify the impact of flour fortification on anaemia in Brazilian children. The survey also investigated the role of Fe deficiency as a cause of anaemia and estimated the bioavailability of the Fe in the children's diet. This local study was complemented by a nationwide survey of the types of Fe compounds added to flour.

Design

Series of population-based surveys conducted in 2004 (baseline study), 2005, 2006 and 2008.

Setting

Pelotas, Rio Grande do Sul, Brazil.

Subjects

Children under 6 years of age residing in the urban area of the city of Pelotas, Southern Brazil (n 507 in 2004; n 960 in 2005; n 893 in 2006; n 799 in 2008). In 2008, a sub-sample of children (n 114) provided venous blood samples to measure body Fe reserve parameters (ferritin and transferrin saturation).

Results

We found no impact of fortification, with an increase in anaemia prevalence among children under 24 months of age. Hb levels decreased by 0·9 g/dl in this age group between 2004 and 2008 (10·9 g/dl to 10·0 g/dl; P < 0·001). Roughly 50 % of cases of anaemia were estimated to be due to Fe deficiency. Half of the mills surveyed used reduced Fe to fortify wheat flour. Total Fe intake from all foodstuffs was adequate for 88·6 % of the children, but its bioavailability was only 5 %.

Conclusions

The low bioavailability of the Fe compounds added to flours, combined with the poor quality of children's diets, account for the lack of impact of mandatory fortification.

Childbearing during adolescence and offspring mortality: findings from three population-based cohorts in southern Brazil

Background

The role of young maternal age as a determinant of adverse child health outcomes is controversial, with existing studies providing conflicting results. This work assessed the association between adolescent childbearing and early offspring mortality in three birth cohort studies from the city of Pelotas in Southern Brazil.

Methods

All hospital births from 1982 (6,011), 1993 (5,304), and 2004 (4,287) were identified and these infants were followed up. Deaths were monitored through vital registration, visits to hospitals and cemeteries. The analyses were restricted to women younger than 30 years who delivered singletons (72%, 70% and 67% of the original cohorts, respectively). Maternal age was categorized into three groups (< 16, 16-19, and 20-29 years). Further analyses compared mothers aged 12-19 and 20-29 years. The outcome variables included fetal, perinatal, neonatal, postneonatal and infant mortality. Crude and adjusted odds ratios (ORs) were estimated with logistic regression models.

Results

There were no interactions between maternal age and cohort year. After adjustment for confounding, pooled ORs for mothers aged 12-19 years were 0.6 (95% CI = 0.4; 1.0) for fetal death, 0.9 (0.6; 1.3) for perinatal death, 1.0 (0.7; 1.6) for early neonatal death, 1.6 (0.7; 3.4) for late neonatal death, 1.8 (1.1; 2.9) for postneonatal death, and 1.6 (1.2; 2.1) for infant death, when compared to mothers aged 20-29 years. Further adjustment for mediating variables led to the disappearance of the excess of postneonatal mortality. The number of mothers younger than 16 years was not sufficient for most analyses.

Conclusion

The slightly increased odds of postneonatal mortality among children of adolescent mothers suggest that social and environmental factors may be more important than maternal biologic immaturity.

How many low birthweight babies in low- and middle-income countries are preterm?

OBJECTIVE: To assess the prevalence of preterm birth among low birthweight babies in low and middle-income countries. METHODS: Major databases (PubMed, LILACS, Google Scholar) were searched for studies on the prevalence of term and preterm LBW babies with field work carried out after 1990 in low- and middle-income countries. Regression methods were used to model this proportion according to LBW prevalence levels. RESULTS: According to 47 studies from 27 low- and middle-income countries, approximately half of all LBW babies are preterm rather than one in three as assumed in studies previous to the 1990s. CONCLUSIONS: The estimate of a substantially higher number of LBW preterm babies has important policy implications in view of special health care needs of these infants. As for earlier projections, our findings are limited by the relative lack of population-based studies.

Óbitos evitáveis até 48 meses de idade entre as crianças da Coorte de Nascimentos de Pelotas de 2004

OBJETIVO: Descrever óbitos evitáveis de crianças pertencentes à Coorte de Pelotas, RS, de 2004. MÉTODOS: O óbito de 92 crianças entre 2004-2008 da Coorte de Pelotas 2004 foi identificado e classificado conforme a Lista de Causas de Mortes Evitáveis por Intervenções do Sistema Único de Saúde. Os Sistemas de Informação sobre Mortalidade (SIM) municipal e estadual foram rastreados para localizar mortes ocorridas fora de Pelotas e as causas após o primeiro ano vida. O óbito de menores de um ano foi avaliado e comparado entre um subestudo e o SIM. Foram calculados coeficientes de mortalidade: 1.000 nascidos vivos (NV), mortalidade proporcional por causas evitáveis e conforme tipo de unidade básica de saúde (tradicional ou Estratégia Saúde da Família). RESULTADOS: O coeficiente de mortalidade foi de 22,2:1.000 NV, 82 óbitos ocorreram no primeiro ano de vida (19,4:1.000 NV), dos quais 37 (45%) na primeira semana. Mais de ¾ dos óbitos (70/92) eram evitáveis. No primeiro ano de vida, a maioria (42/82) das mortes seriam evitadas pela adequada atenção à mulher durante a gestação; de acordo com o SIM, a maioria (n = 32/82), pela adequada atenção ao recém-nascido. Não houve diferença entre o tipo de Unidade Básica de Saúde quanto à proporção de óbitos evitáveis. CONCLUSÕES: É alta a proporção de óbitos infantis que podem ser evitados. Para que os óbitos evitáveis possam ser utilizados como indicadores no monitoramento da qualidade da atenção à saúde materno-infantil, é necessário aprimorar a qualidade dos os registros das Declarações de Óbito.

Maternal-child health in Pelotas, Rio Grande do Sul State, Brazil: major conclusions from comparisons of the 1982, 1993, and 2004 birth cohorts

Important changes were observed in maternal characteristics, health care indicators, and child health during the 22 years covered by the three population-based birth cohort studies conducted in the city of Pelotas, Southern Brazil. Maternal education levels improved, cigarette smoking during pregnancy was reduced, and birth intervals became longer. Also, there were more single mothers, and maternal obesity increased. Coverage of antenatal and delivery care by professionals improved, but inductions and caesarean sections increased markedly, the latter accounting for 45% of deliveries in 2004. With regard to child health, the reductions in neonatal and infant mortality rates were modest, and the significant increase in preterm births--14.7% of all births in 2004--appears to have colluded with this stagnation. Other infant health indicators, such as immunization coverage and breastfeeding duration, showed improvements over the period. Regarding infant nutrition, malnourishment at age 12 months decreased, but the prevalence of overweight was higher in 2004. The existence of three population-based birth cohorts using comparable methodology allowed for the study of important secular trends in maternal and child health.

Mothers and their pregnancies: a comparison of three population-based cohorts in Southern Brazil

Mothers from the 1982, 1993 and 2004 Pelotas birth cohorts were compared across biological, socioeconomic, demographic and reproductive characteristics. Women in the 2004 cohort had higher levels of education, gained more weight during pregnancy, and were heavier at the beginning and end of their pregnancy than mothers who gave birth in 1993 and 1982. There was an important increase in obesity rates (body mass index > 30kg/m²) over the 22 years of the study. Mean parity decreased from 1.3 in 1982 to 1.1 in 2004, with a growing proportion of primiparas and a decline in the proportion of women with > 4 children. The mean birth interval increased from 33.5 months in 1982 to 65.7 in 2004. Smoking during pregnancy decreased from 35.6% in 1982 to 25.1% in 2004. As with other characteristics, the change in smoking status differed according to income, with higher reductions among the wealthiest (from 24.9% to 8.7%) than among the poorest mothers (from 43.7% to 33.6%). In general terms, between 1993 and 2004 there was a decrease in the prevalence of maternal risk factors for unfavorable perinatal outcomes.

Perinatal mortality in three population-based cohorts from Southern Brazil: trends and differences

Trends in perinatal mortality were studied in the city of Pelotas, Southern Brazil, using three population-based cohort studies carried out in 1982, 1993 and 2004. The objective of the present study was to analyze trends and differences in perinatal mortality during the 1982-2004 period. All hospital deliveries and perinatal deaths were monitored through daily visits to maternity wards. Cause of death was determined using information from hospital records and by interviewing physicians. Perinatal mortality fell by 43% in the two decades, with a greater reduction between 1982 and 1993. Intrapartum fetal deaths decreased by 72% and deaths from asphyxia fell from 4.5 per thousand in 1982 to 1.4 per thousand in 2004. In conclusion, reductions in perinatal mortality were also seen across all birth weight categories between 1982 and 1993, but the same was not true for the 1993 to 2004 period, when mortality increased in several categories above 2,000g.

Breastfeeding and feeding patterns in three birth cohorts in Southern Brazil: trends and differentials

Breastfeeding is fundamental for child health. Changes in the duration of breastfeeding are compared for three population-based cohorts of children born in 1982, 1993 and 2004 in the city of Pelotas, Southern Brazil. Samples of the 1982 and 1993 children and all of the children from the 2004 cohort study were sought at home when they were aged around 12 months. Both the duration of breastfeeding and the stage at which different kind of foods were regularly introduced were investigated. The median duration of breastfeeding increased from 3.1 to 6.8 months in this period. Exclusive breastfeeding at three months was practically non-existent in 1982 and had reached one third of infants by 2004. The increase was faster after 1993, suggesting an important impact made by promotion activities. Up to about 6-9 months, breastfeeding was more prevalent in high-income families, but after this age it became more common among the poor. Low birth weight babies were breastfeed for shorter durations. The duration of breastfeeding is still far short of international recommendations, justifying further campaigns. Special attention should be given to low birth weight babies and those from low-income families.