[Risk factors for pre-term birth in Londrina, Paraná State, Brazil]

Racial and ethnic disparities in premature births among pregnant women in the NISAMI cohort, Brazil

The incidence of premature birth has increased worldwide, unequally distributed by race/ethnicity. Racism generates economic inequalities, educational disparities, and differential access to health care, which increases the risk of preterm birth. Thus, this study aimed to evaluate the factors associated with preterm birth and racial and ethnic disparities in premature birth among pregnant women attending prenatal care at the Brazilian Unified Health System health units in the urban area of Santo Antônio de Jesus, Bahia, Brazil. This study used data from 938 pregnant women aged between 18 to 45 years within the NISAMI prospective cohort. Premature birth prevalence was 11.8%, with a higher prevalence among black than non-black women (12.9% versus 6.0%, respectively). Maternal age between 18 and 24 years was the only factor associated with premature birth. A higher risk of premature birth was found among black women than non-black women (RR 3.22; 95%CI 1.42-7.32). These results reveal the existence of racial and social inequalities in the occurrence of premature birth.

Association between preterm births and socioeconomic development: analysis of national data

Background

The increasing prevalence of preterm birth, which is a global phenomenon, is attributable to the increased medical indications, artificial gestations, and some socioeconomic factors. This study was conducted to identify whether development and equality indices are associated with the incidence of preterm birth, specifically, spontaneous and elective preterm births.

Methods

This retrospective observational study comprised an analysis of data on live births from 2019 in Brazil and on socioeconomic indices that were derived from census information in 2017. Data were summarised using absolute and relative frequencies. Spearman’s correlation was used to determine the correlation between socioeconomic factors and the preterm birth rate. Multiple beta regression analysis was performed to determine the best model of socioeconomic covariates and preterm birth rate. The significance level was set at 5%.

Results

In 2019 in Brazil, the preterm birth rate was 11.03%, of which 58% and 42% were spontaneous and elective deliveries, respectively. For all preterm births, Spearman’s correlation varied from ρ = 0.4 for the Gini Index and ρ =  − 0.24 for illiteracy. The best fit modelled the spontaneous preterm birth fraction as a negative function of the Human Development Index (HDI). The best-fit model considered the expected elective preterm birth fraction as a positive function of the HDI and as a negative function of the Gini Index, which was used as a precision parameter.

Conclusions

We observed a reduction in the fraction of spontaneous preterm births; however, the distribution was not uniform in the territory: higher rates of spontaneous preterm birth were noticed in the north, northeast, and mid-west regions. Thus, areas with lower education levels and inequal income distribution have a higher proportion of spontaneous preterm birth. The fraction of elective preterm birth was positively associated with more advantaged indices of socioeconomic status.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-14376-2.

The intergenerational relationship between conditional cash transfers and newborn health

Background

Lack of nutrition, inadequate housing, low education and limited access to quality care can negatively affect children’s health over their lifetime. Implemented in 2003, the Bolsa Familia (“Family Stipend”) Program (PBF) is a conditional cash transfer program targeting poor households in Brazil. This study investigates the long-term benefits of cash transfers through intergenerational transmission of health and poverty by assessing the early life exposure of the mother to the PBF.

Methods

We used data from the 100M SINASC-SIM cohort compiled and managed by the Center for Data and Knowledge Integration for Health (CIDACS), containing information about participation in the PBF and socioeconomic and health indicators. We analyzed five measures of newborn health: low (less than 2,500 g) and very low (less than 1,500 g) birth weight, premature (less than 37 weeks of gestation) and very premature (less than 28 weeks of gestation) birth, and the presence of some type of malformation (according to ICD-10 codes). Furthermore, we measured the early life exposure to the PBF of the mother as PBF coverage in the previous decade in the city where the mother was born. We applied multilevel logistic regression models to assess the associations between birth outcomes and PBF exposures.

Results

Results showed that children born in a household where the mother received BF were less likely to have low birth weight (OR 0.93, CI; 0.92-0.94), very low birth weight (0.87, CI; 0.84-0.89), as well as to be born after 37 weeks of gestation (OR 0.98, CI; 0.97-0.99) or 28 weeks of gestation (OR 0.93, CI; 0.88-0.97). There were no significant associations between households where the mother received BF and congenital malformation.

On average, the higher the early life exposure to the PBF of the mother, the lower was the prevalence of low birth weight, very low birth weight and congenital malformation of the newborn. No trend was noted for preterm birth.

Conclusion

The PBF might have indirect intergenerational effects on children’s health. These results provide important implications for policymakers who have to decide how to effectively allocate resources to improve child health.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12565-7.

Factors associated with preterm birth: from logistic regression to structural equation modeling

This study proposed the application of structural equation modeling (SEM) to investigate variables associated with preterm birth based on a theoretical model analyzed previously by hierarchical logistic regression. The data came from a population-based case-control observational study of hospital births to mothers residing in Londrina, Paraná State, Brazil (June 2006 to March 2007). For the SEM, the study considered the association between socioeconomic characteristics and psychosocial aspects pertaining to reproductive history, work and physical activity, complications during the pregnancy, and fetal characteristics. It also considered the relationship between these associations and the outcome preterm birth mediated by adequacy of prenatal care. The weighted least square mean and variance adjusted estimator (WLSMV) was used for categorical data and robust maximum likelihood (MLR) for odds ratios. Three latent variables were created: socioeconomic vulnerability, family vulnerability, and unwanted pregnancy. The effect of socioeconomic and family vulnerability and unwanted pregnancy on prematurity occurred indirectly through inadequacy of prenatal care. The proposed methodology allowed using constructs, verifying the role of mediation by inadequacy of prenatal care, and identifying the variables' direct and indirect effects on the outcome preterm birth.

Premature childbirth: pregnant women's characteristics of a population in the South area of São Paulo

Abstract Objectives: to identify the characteristics of pregnant women who had premature child-birth (PPT) in the South region of São Paulo city. Methods: a cross-sectional observational study with a data collection of 122 medical files on pregnant women who had PPT in 2013. The collected data were analyzed by a statistical package, Graphpad Prism 6. As for the variables that were shown to be significant in the multivariate regression, an analysis was performed in a dichotomous form by odds ratio. Results: the mean age of the pregnant women was 24.9 years old. Of the 122 pregnant women, 34.4% were included in the age group considered to be at risk by the Ministry of Health. The predominant race was mixed (46.2%). 41.8% were high school graduates. Regarding to personal background, the history on urinary infection was mostly mentioned (37.5%). In relation to family history regarding clinical conditions, 43% had diabetes history and 61% had hypertension. As for gynecological history, 37.5% reported having dysmenorrhea during menstrual cycles. Multivariate analysis was performed and found that particularly hypertension and dysmenorrhea were the most significant. Conclusions: Regarding to women´s risk factors for premature childbirth, the most determining factor was dysmenorrhea, followed by hypertension.

Atenção nutricional no pré-natal e no puerpério: percepção dos gestores da Atenção Básica à Saúde

RESUMO Objetivo: Avaliar a percepção dos gestores quanto à atenção nutricional ao pré-natal e ao puerpério na rede básica de município da Baixada Santista, São Paulo, segundo estrutura e processo. Métodos: Realizou-se censo das 28 unidades básicas da área insular por meio de entrevistas com gestores. Avaliou-se a atenção nutricional segundo infraestrutura, processo de trabalho e vigilância alimentar e nutricional. Resultados: A inserção do nutricionista foi o principal componente insuficiente da dimensão estrutura, interferindo negativamente na atenção nutricional para 60% dos gestores. Encontrou-se baixa conformidade para as seguintes variáveis da dimensão processo: cálculo do índice de massa corporal (35%), acompanhamento do estado nutricional na curva índice de massa corporal/semana gestacional (46%) e realização de aconselhamento nutricional individualizado no pré-natal (14%). Conclusão: A atenção nutricional pré-natal e puerperal é insatisfatória para alcançar a integralidade do cuidado. Faz-se necessário sensibilizar gestores locais e capacitar equipes de saúde para assegurar a efetividade de tais ações em Santos.

O crescimento e desenvolvimento frente à prematuridade e baixo peso ao nascer

<p>Objetivo: Realizar um levantamento bibliográfico acerca do crescimento e desenvolvimento de prematuros e/ou com baixo peso ao nascer. Metodologia: Utilizaram-se as bases de dados LILACS, MEDLINE e ELO. Foram encontrados 64 trabalhos: 10 publicados em 2005, 10 em 2006, 12 em 2007, 16 em 2008, 8 em 2009 e 8 em 2010. As publicações situaram-se nas áreas da medicina (59,4%), nutrição (7,8%), enfermagem (7,8%), saúde coletiva (7,8%), psicologia (6,2%), epidemiologia (4,7%), fisiologia (3,1%) e fonoaudiologia (3,1%). Resultados: Os textos encontrados permitiram organizar o conhecimento produzido segundo as seguintes categorias de análise: Fatores associados ao baixo peso ao nascer/prematuridade. Repercussões do baixo peso ao nascer/prematuridade para o crescimento e desenvolvimento e medidas de prevenção e Sobrevida dos recém-nascidos prematuros e/ou de baixo peso. Conclusão: As crianças nascidas prematuramente e com baixo peso geralmente apresentam déficit de desenvolvimento. Um acompanhamento pós-natal focado no crescimento e desenvolvimento torna-se essencial.</p>

The Growing Trend of Moderate Preterm Births: An Ecological Study in One Region of Brazil

Background

Preterm birth is a serious public health problem, as it is linked to high rates of neonatal and child morbidity and mortality, with Brazil listed among the countries with the ten highest numbers of premature births. Nonetheless, knowledge is scarce regarding prematurity and associated factors in mid-sized cities. The objective of this study was to analyze the trend of preterm births and associated factors in a municipality located in the state of Paraná, Brazil.

Methods

This was an ecological time series study of births recorded into the Live Birth Information System for residents of Maringá, Paraná, Brazil, between 2000 and 2013. The polynomial regression model was used for trend analysis of preterm birth, characteristics of the mother, gestation and delivery, and newborn. The association with preterm birth was analyzed using odds ratio (OR).

Results

A total of 61,634 live births were analyzed, of which 5,632 were preterm births. Prematurity increased from 7.9% in 2000 to 11.2% in 2013 –an average increase of 0.54% per year (r² = 0.93)–with a growing share of moderate preterm births (32 to <37 weeks), which rose from 7.0% in 2000 to 9.7% in 2013. Between 2011 and 2013, multiple pregnancy (OR = 16.64; CI = 13.24–20.92), inadequate number of prenatal visits (OR = 2.81; CI = 2.51–3.15), Apgar score below 7 at 1 (OR = 4.07; CI = 3.55–4.67) and 5 minutes (OR = 10.88; CI = 7.71–15.36), low birth weight (OR = 38.75; CI = 33.72–44.55) and congenital malformations (OR = 3.18; CI = 2.14–4.74) were associated with preterm birth. A growing trend was observed for multiple pregnancies, with an average annual increase of 0.32% (r² = 0.90), as well as for C-section birth (2.38% yearly increase). Of all newborn characteristics, Apgar score below 7 at 5 minutes (-0.19% per year) and low birth weight (-1.43%) decreased, whereas congenital malformations rose (0.20% per year).

Conclusions

Efforts are required to prevent premature delivery, particularly during the moderate period, as well as greater care during the prenatal period towards expectant mothers bearing multiple pregnancies, birth defects, in addition to reducing C-section birth as it may be linked to preterm birth.

What is the impact of interventions that prevent fetal mortality on the increase of preterm live births in the State of Sao Paulo, Brazil?

Background

There is a global growing trend of preterm births and a decline trend of fetal deaths. Is there an impact of the decline of fetal mortality on the increase of preterm live births in State of Sao Paulo, Brazil?

Methods

The time trends were evaluated by gestational age through exponential regression analysis. Data analyzed included the fetal mortality ratio, proportion of preterm live births, fertility rate of women 35 years and over, prenatal care, mother's education, multiple births and cesarean section deliveries. A survival analysis was carried out for 2000 and 2010.

Results

Preterm births showed the highest annual increase (3.2 %) in the less than 28 weeks of gestation group and fetal mortality ratio decreased (7.4 %) in the same gestational age group. There was an increase of cesarean section births and it was higher in the < 28 weeks group (6.1 %). There was a decreased annual trend of mothers with inadequate prenatal care (6.1 %) and low education (8.8 %) and an increased trend in multiple births and fertility rates of women of 35 years and over. The variables were highly correlated to which other over time. In 2000, 8.2 % of all pregnancies resulted in preterm births (0.9 % in fetal deaths and 7.3 % in live births). In 2010, the preterm birth increased to 9.4 % (0.8 % were preterm fetal deaths and 8.6 % preterm live births).

Conclusions

The results suggest that 45.2 % could be the maximum contribution of successful interventions to prevent a fetal death on the increase in preterm live births. This increasing trend is also related to changes of the women reproductive profile with the change of the women reproductive profile and access to prenatal care.

Mortalidade infantil na percepção de gestores e profissionais de saúde: determinantes do seu declínio e desafios atuais em município do sul do Brasil

Este estudo objetivou analisar a percepção de gestores e profissionais da saúde sobre os determinantes para o declínio da mortalidade infantil nas últimas décadas, bem como os desafios para a continuidade da redução dos valores desse indicador em Londrina (PR). Foi realizado uma pesquisa qualitativa com análise de entrevistas de 38 gestores, profissionais de saúde e pesquisadores, selecionados pela técnica da bola de neve. Na visão dos entrevistados, os determinantes para a redução da mortalidade infantil foram melhorias das condições de vida e medidas implantadas por políticas públicas e ações setoriais e extrassetoriais. Os desafios atuais dizem respeito, principalmente, à qualificação da assistência pré-natal, à redução da gravidez na adolescência, à melhoria da atenção hospitalar ao recém-nascido prematuro, à prevenção da prematuridade e ao financiamento do Sistema Único de Saúde (SUS). O aumento da proporção de mortes neonatais torna mais complexo e difícil reduzir a mortalidade infantil. Compreender as dificuldades e identificar os desafios, sob a percepção de gestores e profissionais da saúde, pode contribuir para o planejamento das ações necessárias para a melhoria da saúde das crianças menores de 1 ano e para a redução da mortalidade infantil.

Perfil das patologias prevalentes na gestação de alto risco em uma maternidade escola de Maceió, Alagoas, Brasil

Objetivos: Descrever o perfil epidemiológico das patologias prevalentes na gestação de alto risco na Maternidade Escola Santa Mônica, município de Maceió, Alagoas. Métodos: Estudo epidemiológico, transversal e retrospectivo, realizado por meio da análise descritiva dos dados de prontuários de gestantes atendidas por ocasião do parto no período de janeiro de 2006 a novembro de 2010. Foram incluídos prontuários das gestantes de alto risco atendidas na maternidade no período estudado e excluídos da pesquisa os prontuários não preenchidos corretamente ou incompletos quanto às patologias prevalentes na gestação de alto risco. O cálculo amostral foi realizado a partir do teste de hipótese para uma proporção, segundo Lwanga e Lemeshow. A coleta de dados foi realizada por meio de preenchimento de formulário contendo informações dos prontuários, desenvolvido para esta pesquisa. As variáveis foram: patologias prevalentes na gestação de alto risco, idade materna, paridade, tipo de parto e tempo de gestação. Resultados: Foram analisados 316 prontuários. O trabalho de parto prematuro foi a patologia mais prevalente, representando 31,4% (98/312; IC95% 26,5 a 36,8) das patologias de alto risco. Em relação à idade materna, 72,7% (227/312; IC95% 67,5 a 77,4) das gestantes eram jovens (<30 anos). Quanto ao número de gestações, as multíparas corresponderam a 52,9% (165/312; IC95% 47,3 a 58,3). Considerando o tipo de parto, 59,0% (184/312; IC95% 53,4 a 64,3) foram cesáreos. Quanto ao tempo de gestação, 47,4% (148/312; IC95% 42,0 a 53,0) foram prematuros. Conclusões: O perfil epidemiológico encontrado foi o trabalho de parto prematuro em gestantes jovens e multíparas que evoluíram para um parto cesariano e pré-termo. 

Smoking and adverse maternal and child health outcomes in Brazil

INTRODUCTION

Numerous studies from high-income countries document the causal relationship between cigarette smoking during pregnancy and adverse maternal and child health (MCH) outcomes. Less research has been conducted in low and middle income countries, but a burgeoning literature can be found for Brazil.

METHODS

We review Brazilian studies of the prevalence of maternal smoking, the relative risk of smoking-attributable adverse MCH outcomes, and present new estimates for these outcomes, using the attributable fraction method.

RESULTS

We found that Brazilian studies of the relative risks of smoking-attributable adverse MCH outcomes were broadly consistent with previous reviews. Based on a comparison of maternal smoking over time, smoking during pregnancy has declined by about 50% over the last 20 years in Brazil. For 2008, we estimate that 5,352 cases of spontaneous abortion, 10,929 cases of preterm birth, 20,717 cases of low birth weight, and 29 cases of sudden infant death syndrome are attributable to maternal smoking. Between 1989 and 2008, the percent of smoking-attributable adverse MCH outcomes in Brazil was at least halved.

CONCLUSIONS

The results show that over a 20-year period, during which Brazil implemented numerous effective tobacco control measures, the country experienced a dramatic decrease in both maternal smoking prevalence and smoking-attributable adverse MCH outcomes. Countries that implement effective tobacco control measures can expect to reduce both maternal smoking and adverse MCH outcomes, thereby improving the public health.

Avaliação da qualidade da atenção pré-natal dentre gestantes com e sem história de prematuridade no Sistema Único de Saúde no Rio de Janeiro, Brasil

OBJETIVOS: avaliar adequação, acompanhamento pré-natal, satisfação e riscos gestacionais das gestantes com história de prematuridade. MÉTODOS: estudo seccional com 1239 gestantes, 259 com história de prematuridade no Sistema Único de Saúde (SUS) do RJ em 2007/2008. Informações demográficas, socio-econômicas, história obstétrica, adequação pré-natal e satisfação foram coletadas através de entrevistas e do cartão pré-natal. Utilizou-se teste χ² para comparar o grupo com história de prematuridade com os grupos de baixo risco e sem história de prematuridade. RESULTADOS: não houve diferenças na adequação e no cuidado pré-natal entre as gestantes com história de prematuridade comparadas às de baixo risco gestacional. Houve insatisfação com tempo de espera pelas consultas, horário de funcionamento das unidades de saúde e explicações dos profissionais de saúde. CONCLUSÕES: a presença de história de prematuridade não influenciou para que essas gestantes tivessem um pré-natal de melhor qualidade. As unidades de saúde apresentaram problemas, segundo a percepção das gestantes, em relação ao modo de funcionamento. As explicações dos profissionais de saúde sobre risco da prematuridade não atenderam às expectativas das gestantes.

Macroscopic placental changes associated with fetal and maternal events in diabetes mellitus

OBJECTIVES

The current study sought to identify macroscopic placental changes associated with clinical conditions in women with or without diabetes and their newborns.

METHODS

The study population consisted of 62 pregnant women clinically diagnosed with diabetes and 62 healthy women (control group).

RESULTS

Among the subjects with diabetes, 43 women (69.3%) were diagnosed with gestational diabetes mellitus, 15 had diabetes mellitus I (24.2%), and four had diabetes mellitus II (6.5%). The mean age of the women studied was 28.5 ± 5.71 years, and the mean gestational age of the diabetic women was 38.51 weeks. Of the 62 placentas from diabetic pregnancies, 49 (79%) maternal surfaces and 59 (95.2%) fetal surfaces showed abnormalities, including calcium and fibrin deposits, placental infarction, hematoma, and fibrosis. A statistical association was found between newborn gender and fetal and maternal placental changes (p = 0.002). The mean weight of the newborns studied was 3,287 ± 563 g for women with diabetes mellitus, 3,205 ± 544 g for those with gestational diabetes mellitus, 3,563 ± 696 g for those with diabetes mellitus II, and 3,095 ± 451 g for those with diabetes mellitus I.

CONCLUSIONS

Infarction, hematoma, calcification, and fibrin were found on the maternal and fetal placental surfaces in women with diabetes. Women with gestational diabetes and post-term infants had more calcium deposits on the maternal placental surface as compared to those with type I and type II diabetes.

Fatores associados ao nascimento pré-termo em Campina Grande, Paraíba, Brasil: um estudo caso-controle

Estudo caso-controle (2008-2009) de base populacional que analisou fatores de risco para nascimento pré-termo em Campina Grande, Paraíba, Brasil. Foram incluídos 341 nascimentos pré-termo e 424 controles. Utilizou-se regressão logística múltipla. Foram fatores de risco: idade materna de 35 ou mais (OR = 2,00; IC95%: 1,00-4,03), pré-termo prévio (OR = 2,32; IC95%: 1,25-4,29), pré-natal inadequado (OR = 2,15; IC95%: 1,40-3,27), ganho ponderal materno insuficiente (OR = 2,33; IC95%: 1,45-3,75), dano físico materno (OR = 2,10; IC95%: 1,22-3,60), hipertensão arterial com eclampsia (OR = 17,08; IC95%: 3,67-79,43) e sem eclampsia (OR = 6,42; IC95%: 3,50-11,76), internação (OR = 5,64; IC95%: 3,47-9,15), alteração do volume amniótico (OR = 2,28; IC95%: 1,32-3,95); sangramento vaginal (OR = 1,54; IC95%: 1,01-2,34) e gestação múltipla (OR = 22,65; IC95%: 6,22-82,46). Elevada e homogênea prevalência de pobreza e baixa escolaridade pode ter contribuído para que as variáveis socioeconômicas não permanecessem com associação significativa para o nascimento pré-termo.

Fatores de risco maternos para prematuridade em uma maternidade pública de Imperatriz-MA

Apesar dos avanços da obstetrícia, a prematuridade ainda se configura como um dos grandes problemas de saúde pública, em virtude da morbidade e da mortalidade neonatal que causa. O objetivo deste estudo foi investigar fatores de risco maternos para nascimentos de prematuros em uma maternidade pública de Imperatriz-MA. Um estudo comparativo transversal foi realizado com 116 puérperas, por meio de entrevistas estruturadas. Os dados coletados foram analisados através do Software Epi-Info, versão 3.5.1. As variáveis que tiveram associação estatisticamente significante com a prematuridade foram: renda mensal inferior a 2 salários mínimos (p=0,046); estresse na gestação (p=0,027); primiparidade (p=0,044); assistência pré-natal ausente ou inadequada (p<0,001); e intercorrências clínicas na gestação (p=0,001). Os resultados apontam que os fatores de risco maternos implicados na prematuridade estão relacionados, sobretudo, com hábitos de vida, assistência pré-natal e condições socioeconômicas e clínicas.

Qualidade do processo da assistência pré-natal: unidades básicas de saúde e unidades de Estratégia Saúde da Família em município no Sul do Brasil

O processo da atenção pré-natal em unidades básicas de saúde tradicionais (UBS) e unidades de Estratégia Saúde da Família (ESF) foi avaliado em Santa Maria, Rio Grande do Sul, Brasil. Foram entrevistadas 795 puérperas que realizaram pré-natal nas UBS ou ESF. Utilizou-se quatro níveis de qualidade: nível 1 (índice de Kessner modificado por Takeda); nível 2, que adiciona ao nível 1 procedimentos clinico-obstétricos; nível 3, que acrescenta ao nível 1 exames laboratoriais; e nível 4, que considera todos os parâmetros anteriores. A atenção pré-natal realizada na ESF foi superior a das UBS em todos os níveis, com diferenças estatisticamente significativas nos níveis 1 e 2. As gestantes da ESF receberam mais orientações. A atenção pré-natal foi favorável à ESF, devendo ser melhorada em relação aos procedimentos e exames, a fim de aprimorar a assistência pré-natal e fortalecer a atenção primária à saúde.

[Survival and risk factors for neonatal mortality in a cohort of very low birth weight infants in the southern region of São Paulo city, Brazil]

Population studies can help identify the complex set of risk factors for neonatal mortality among very low birth weight infants. A cohort (2000-2001) of 213 live newborns with birth weight < 1,500g in the southern region of São Paulo city, Brazil, was studied (112 neonatal deaths and 101 survivors). Data were obtained from home interviews and hospital records. Survival analysis and multiple Cox regression were performed. The high mortality in the delivery room and in the first day of life among neonates < 1,000g and < 28 weeks gestational age and the absence of survival in neonates < 700g suggest that care was actively oriented towards newborns with better prognosis. Increased risk of neonatal mortality was associated with maternal residence in slum areas, history of previous cesarean(s), history of induced abortion(s), adolescent motherhood, vaginal bleeding, and lack of prenatal care. Cesarean section and referral of the newborn to the hospital nursery showed protective effects. Birth weight less than 1,000g and Apgar index < 7 were associated with increased risk. The high mortality was due to poor living conditions and to maternal and neonatal characteristics. Improvement in prenatal and neonatal care could reduce neonatal mortality in these infants.

[Challenges in definition of gestational age in population studies on birth preterm: the case of a study in Campina Grande (PB), Brazil]

INTRODUCTION

The prevalence of preterm birth has increased in recent years and it is currently a worldwide public health problem. In any epidemiological study, the greatest challenge facing the study of preterm delivery is to standardize the measurement of gestational age births.

OBJECTIVE

To describe the methods used to define the sample under study and selection of events in case-control studies of risk factors for preterm birth in hospital births by mothers living in the city of Campina Grande (PB), Brazil.

METHODS

The design was a case-control population-based, which was conducted from June 2008 to May 2009. The cases were born at less than 37 weeks of gestation and controls at 37 weeks or more. Gestational age in weeks was defined using selection criteria based on the accuracy of the estimate. Interviews were conducted with mothers and collection of hospital records.

RESULTS

It was selected 341 cases and 424 controls, 13.19% were classified as extremely preterm (<28 weeks), 34.87% as very preterm (<33 weeks) and 65.10% as moderate preterm (33 to 36 weeks of gestation). Among controls, the percent of children born 37-39 weeks was 58.02 to 5.90% was born post term (>42 weeks).

CONCLUSION

The strategies shown to be viable, even in a context with major limitations in obtaining the necessary information, given that the profile of preterm infants, the distribution of gestational age were comparable to studies with more accurate methods.