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O R IG IN A L A R T IC L E Eddie Fernando Candido Murta Guilherme Carvalho Freire Daniel Capucci Fabri Renato Humberto Fabri Could elective cesarean sections infl uence the birth weight of full-term infants? Discipline of Gynecology and Obstetrics, Universidade Federal do Triângulo Mineiro (UFTM), Uberaba, Minas Gerais, Brazil INTRODUCTION Increasing cesarean section rates are a worldwide phenomenon, especially in Brazil, but they still cannot be fully explained. The culture of cesareans in Brazil affects obstetricians and society in general. One of the causes of the increasing cesarean section rates in Brazil is the predominantly elective nature of the indications, which are seen mainly in private hospitals. Elective cesarean section rates have also been increasing around the world. Neonatal respiratory distress risks may be a complication in elective cesarean sections. In Brazil, some studies have showed increased rates of preterm births and low birth weight (< 2500 g), probably due to iatrogenic practices related to elective cesarean sections. But to our knowledge, there have not been any studies on birth weights of full term infants born by means of elective cesarean section. Dystocia is more frequent in prolonged gestation, because of the increased fetal weight. Since birth weight increases as pregnancy progresses, the question that arises is whether elective cesarean section performed prior to spontaneous labor could infl uence the birth weight. In theory, infants born from elective cesarean section at a gestational age of 37 weeks will have lower birth weight than if they were born at a gestational age of 40 weeks. OBJECTIVE We had the aim of studying birth weights among full-term infants born from cesarean section and vaginal delivery at private hospitals and public hospitals. METHODS A retrospective study was conducted at Universidade Federal do Triângulo Mineiro, Uberaba, Brazil, from January to December 2000, in which data were collected from the municipal medical birth register of Uberaba. Maternal age, type of delivery, number of prenatal care visits and birth weights of newborns from full-term pregnancies (3741 weeks of gestation) were analyzed. The length of gestation was measured from the fi rst day of the last menstrual period. Twin pregnancies were excluded. We compared data obtained from the university hospital (UH) and four private hospitals (PHs). The UH is a tertiary hospital that only attends patients within the National Health System (SUS) who have an obstetric indication for cesarean section. This hospital provides free attendance for a population of low socioeconomic and educational levels. The PHs provide attendance for patients with health insurance plans and private patients and accept elective indication for cesarean section. These patients have higher socioeconomic and educational levels. Student’s t test, χ test and multiple logistic regression were used for statistical analysis, with the signifi cance level set at p < 0.05. The Graph Pad Prism 3.0, Statistical Package for Social Sciences (SPSS) and Epi Info 6.04 software were used for data analysis. It was calculated that the sample size should be at least 250 (Student’s t test with mean difference of 100 grams and anticipated standard deviation of 400 grams; χ test with difference of 20%; both with statistical power of 80%). This research was approved by the Research Ethics Committee of Universidade Federal do Triângulo Mineiro. RESULTS The type of medical attendance exerted an infl uence on the type of delivery and in birth weight among the expectant CONTEXT AND OBJECTIVE: There are no studies on birth weights among full-term infants born by means of elective cesarean section. We aimed to study this in private and public hospitals. DESIGN AND SETTING: Retrospective study at Universidade Federal do Triângulo Mineiro, Uberaba, Brazil. METHODS: Data were collected from the municipal medical birth register of Uberaba from January to December 2000. The data obtained (maternal age, type of delivery, number of prenatal care visits and birth weight, from full-term pregnancy) from the university hospital (UH), which is a tertiary hospital that only attends patients within the National Health System (SUS), were compared with data from four private hospitals (PHs) that attend health insurance plans and private patients. Student’s t test, χ2 test and multiple logistic regression were used for statistical analysis, with the signifi cance level set at p < 0.05. RESULTS: In the PHs, 1,100 out of 1,354 births (81.2%) were by cesarean section and in the UH, 373 out of 1,332 (28%). Birth weight increased signifi cantly in association with increasing numbers of prenatal care visits, except for cesarean section cases in PHs. Birth weights among vaginal delivery cases in PHs were greater than in the UH (p < 0.05), but this was not observed among cesarean section cases. Multiple logistic regression showed that there was greater risk of low birth weight in PHs (odds ratio: 2.33; 95% confi dence interval: 1.19 to 4.55). CONCLUSION: Elective cesarean section performed in PHs may be associated with low birth weight among full-term infants.