Brazilian regional differences and factors associated with the prevalence of cesarean sections

Abstract Introduction: Brazil presents high C-section prevalence rates. Several factors may be associated with such high rates. Objective: To observe and analyze factors associated with the prevalence of cesarean sections in Brazil, according to their occurrence in Brazilian regions. Methods: An ecological study, having C-section as the outcome, from 1990 to 2013, in Brazilian regions, using data from the Brazilian National Health Survey, 2013. Records of women in their reproductive period, aged between 18 and 49 years, were included, totaling a sample of 16,175 women. Descriptive and bivariate analysis was carried out with logistic regression. Results: The prevalence of cesarean sections in Brazil was 53.03%. Vaginal delivery was more prevalent in the North (52.74%) and Northeast (51.06%) regions, while C-section was more prevalent in the Southeast (59.32%), South (56.96%) and Midwest (61.48%) regions. Over the years, an increased probability of cesarean sections was observed, particularly in the following regions: Northeast (2.21 times more, CI95%: 1,42 - 3,46) and South (2.75 times more, CI95%: 1,44 - 5,23). Women with higher levels of education are 2.05 times (CI95%: 1.27 - 3.30) more likely to have a C-section, especially those in the Northern and Southern regions. In the Northeast, this probability increased, regardless of the level of education. Conclusion: The prevalence of cesarean sections in Brazil is high and, over the years, factors such as level of education, maternal age and having health insurance, seem to contribute to the increase in surgical deliveries.

引言：巴西剖宫产（cesarean section，简称C-section）患病率居高不下，多种因素或与此高患病率相关。
研究目的：本研究旨在结合巴西各地区的剖宫产发生情况，观察并分析与该国剖宫产患病率相关的影响因素。
研究方法：本研究为生态学研究，以剖宫产为结局指标，纳入1990年至2013年巴西各地区的相关数据，数据来源于2013年巴西全国健康调查（Brazilian National Health Survey, 2013）。研究对象为18~49岁的育龄女性，最终纳入样本量共计16175名。本研究采用描述性分析、双变量分析及逻辑回归（logistic regression）开展统计分析。
研究结果：巴西整体剖宫产患病率为53.03%。阴道分娩在北部（52.74%）和东北部（51.06%）地区更为普遍，而剖宫产在东南部（59.32%）、南部（56.96%）及中西部（61.48%）地区占比更高。随时间推移，剖宫产发生概率呈上升趋势，其中东北部（比值比为2.21，95%置信区间[CI95%]：1.42~3.46）和南部（比值比为2.75，95%置信区间[CI95%]：1.44~5.23）地区的上升幅度尤为显著。受教育程度较高的女性接受剖宫产的概率为其他女性的2.05倍（95%置信区间[CI95%]：1.27~3.30），这一关联在北部和南部地区尤为突出。而在东北部地区，无论受教育程度如何，剖宫产发生概率均有所提升。
研究结论：巴西剖宫产患病率居高不下，随时间推移，受教育程度、产妇年龄及拥有医疗保险等因素，均可能推动手术分娩比例的上升。