RESUMO
INTRODUCTION: Caesarean section (C/S) rates have significantly increased across the world over the past decades. In the present population-based study, we sought to evaluate the association between C/S and neonatal mortality rates. MATERIAL AND METHODS: This retrospective ecological study included longitudinal data of 166 countries from 2000 to 2015. We evaluated the association between C/S rates and neonatal mortality rate (NMR), adjusting for total fertility rate, human development index (HDI), gross domestic product (GDP) percentage, and maternal age at first childbearing. The examinations were also performed considering different geographical regions as well as regions with different income levels. RESULTS: The C/S rate and NMR in the 166 included countries were 19.97% ± 10.56% and 10 ± 10.27 per 1000 live birth, respectively. After adjustment for confounding variables, C/S rate and NMR were found correlated (r = -1.1, p < 0.001). Examination of the relationship between C/S rate and NMR in each WHO region resulted in an inverse correlation in Africa (r = -0.75, p = 0.005), Europe (r = -0.12, p < 0.001), South-East Asia (r = -0.41, p = 0.01), and Western Pacific (r = -0.13, p = 0.02), a direct correlation in America (r = 0.06, p = 0.04), and no correlation in Eastern Mediterranean (r = 0.01, p = 0.88). Meanwhile, C/S rate and NMR were inversely associated in regions with upper-middle (r = -0.15, p < 0.001) and lower-middle (r = -0.24, p < 0.001) income levels, directly associated in high-income regions (r = 0.02, p = 0.001), and not associated in low-income regions (p = 0.13). In countries with HDI below the centralized value of 1 (the real value of 0.9), the correlation between C/S rate and NMR was negative while it was found positive in countries with HDI higher than the mentioned cut-off. CONCLUSIONS: This study indicated that NMR associated with C/S is dependent on various socioeconomic factors such as total fertility rate, HDI, GDP percentage, and maternal age at first childbearing. Further attentions to the socioeconomic status are warranted to minimize the NMR by modifying the C/S rate to the optimum cut-off.