Neonatal mortality inequalities in Peru, 2007-2021: an ecological joinpoint trends analysis

Neonatal disorders remain a leading cause of loss of healthy life years worldwide, second only to COVID-19 in 2021, although most neonatal deaths are preventable. The neonatal mortality rate (NMR), a key indicator of the 2030 Sustainable Development Agenda, varies widely within and between countries, reflecting social conditions that shape neonatal survival. This study examined the magnitude and temporal trends of ecosocial inequalities in Peru's NMR from 2007 to 2021, their relationship with selected social determinants, and changes in the epidemiological profile of neonatal deaths.

An ecological study was conducted using data from Peru's 25 regions (2007-2021). Temporal trends in NMR and inequalities along a social gradient defined by monetary poverty, unmet basic needs, and food insecurity were analyzed. Absolute and relative inequalities were measured using the slope index of inequality (SII) and concentration index (CIx). Inflection points in trends were identified with joinpoint regression, and monotonic associations between NMR (and its inequalities) and contextual variables were assessed using Spearman's rank correlation. Changes in the epidemiological profile of neonatal deaths were evaluated with the Chi-square test.

Peru's NMR declined from 10.3 to 8.8 deaths per 1,000 live births between 2007 and 2021, with the steepest reduction around 2010-2014. Most regions experienced decreases, except Huancavelica, Pasco, and Puno. Cross-regional inequalities showed a persistent pro-rich pattern, indicating survival disadvantages in regions with higher unmet basic needs. National NMR trends correlated positively with unmet basic needs and monetary poverty and negatively with current health expenditure per capita. During the COVID-19 years, inequalities narrowed as NMR fell in poorer regions and rose in richer ones. The epidemiological profile shifted toward a higher proportion of deaths from extreme prematurity and low birth weight.

From 2007 to 2021, Peru achieved a decline in neonatal mortality, but pro-rich regional inequalities persisted, and the burden remained concentrated in highland regions. During the COVID-19 period, the downward trend continued while inequalities narrowed, in parallel with reductions in poverty and increases in health expenditure. These ecological findings highlight the importance of monitoring health inequalities alongside national averages to support accountability toward the SDG commitment to "leave no one behind."