[Social inequalities in under-five mortality: a systematic review]

To identify the characteristics of the published studies on social inequalities in under-five mortality, their theoretical perspectives, axes of inequality, methods and results.

We carried out a systematic literature review. We consulted four electronic databases and Google Scholar, for studies published between 2010 and 2018.

We analyzed 126 articles. In 62.7%, territory was studied as the axis of inequality, followed by socioeconomic determinants (27.8%). Neonatal, infant and under-five mortality was analyzed as an output in health in 19.0%, 49.2% and 32.3%, respectively. It predominated ecological (62.7%) and longitudinal (50.0%) studies. Significant reductions in mortality rates were found, however, the decline was not homogeneous among subpopulations.

The literature reports a marked decrease in under-five mortality; however, the gaps between different axes of inequality continue and in some cases they have increased. Gaps varied according to time, place, axis of inequality and type of mortality analyzed.