[Social inequalities in cesarean section rates in primiparae, Southern Brazil].

OBJECTIVE To investigate the effect of social inequalities in cesarean section rates among primiparae having single pregnancy and delivering in maternity hospitals. METHODS The study was carried out in Southern Brazil in 1996, 1998 and 2000. Data from the Live Birth National Information System were used to estimate annual rates and crude and adjusted odds ratios (OR) of cesarean sections according to social conditions (maternal age and education, newborn skin color/ethnicity and macro-regions), duration of pregnancy, and number of prenatal visits. RESULTS The overall cesarean section rate was 45%, and above 37% in all macro-regions. Increased rates were seen among native and black mothers, aged 30 years or more, living in metropolitan, river valley and mountain macro-regions and having attended to more than six prenatal visits. Crude and adjusted OR show that cesarean rates were negatively associated with all categories of skin color/ethnicity when compared to white newborns, particularly those of native Brazilian (ORadj=0.43; 95% CI: 0.31-0.59), and they were positively associated with higher maternal education (ORadj=3.52; 95% CI: 3.11-3.99), older age (ORadj=6.87; 95% CI: 5.90-8.00) and greater number of prenatal visits (ORadj=2.16; 95% CI: 1.99-2.35). The effects of age and education were partly mediated by the greater number of prenatal visits among higher educated older women. The OR varied among macro-regions but were greater for the wealthier mountain region. CONCLUSIONS High rates of cesarean section rates in Southern Brazil are a public health concern. They are associated with social, economic and cultural factors which can lead to misuse of medical technology during labor and delivery.