Objectives: This study aimed to examine the prevalence of spontaneous labour, induced labour and planned caesarean section in low-risk women; to identify the contribution of each group to the overall caesarean section rate; and to estimate factors associated with caesarean section in low-risk women according to spontaneous labour, induced labour and planned caesarean section.
Design: Cross-sectional hospital-based study of postpartum women and newborns, using data from the survey Birth in Brazil, Southern region. In the sample of 2,668 low-risk women, a descriptive analysis was undertaken and a Multinomial Logistic Regression model was applied to verify associations among caesarean section and spontaneous labour, induced labour and planned caesarean section in comparison with vaginal birth.
Measurements and findings: The results showed the prevalence of spontaneous labour (48.0%), induced labour (14.0%) and planned caesarean sections (38.0%); these frequencies contributed to an overall caesarean section rate of 50.5%. Obstetric characteristics like previous vaginal birth or previous caesarean section were differentially associated with caesarean section, independently of the labour. Caesarean section without labour was significantly associated with age ≥ 35 years (ORadj 5.45 95%CI 3.16-9.39), economic class A and B (ORadj 3.10 95%CI 1.92-4.99), pregnancy between 37 and 38 weeks (ORadj 1.65 95%CI 1.22-2.24), same obstetrician in prenatal and childbirth (ORadj 13.83 95%CI 8.85-21.61) and private payment source at birth (ORadj 11.50 95%CI 6.64-19.93).
Key conclusion: For low-risk women in Southern Brazil, the results identify high planned caesarean section rates, not associated with socioeconomic, obstetric, institutional or prenatal factors that justify these rates.
Keywords: Caesarean section; Induction; Labour; Obstetric; Parturition; Prevalence.
Copyright © 2019. Published by Elsevier Ltd.