Temporal and spatial trends in isolated gastroschisis: a population-based study in a middle-income setting.

Objective: To estimate the prevalence and neonatal mortality of isolated gastroschisis, assess temporal trends, identify risk factors for neonatal death, and describe its spatial distribution in a middle-income setting. Methods: This population-based study included all live births in São Paulo State, Brazil, from 2004 to 2017. Cases of isolated gastroschisis were identified from live birth and death certificates. Temporal trends in prevalence and neonatal mortality (0-27 days) were analyzed using Prais-Winsten regression to estimate annual percent change (APC). Maternal and neonatal factors associated with neonatal death were examined using Poisson and multivariate logistic regression. Spatial distribution across municipalities was described by quartiles according to maternal residence. Results: Among 8,441,498 live births, 1664 cases of isolated gastroschisis were identified (prevalence: 1.97 per 10,000). Neonatal mortality rate associated with isolated gastroschisis was 0.35 per 10,000 live births, with a lethality rate of 17.7%. Prevalence (APC 3.0%; 95% CI: -1.3 to 7.5) and mortality (0.6%; -3.5 to 4.8) remained stable over time. Lower gestational age, fewer prenatal visits, and severe growth restriction were independently associated with higher risk of neonatal death. Spatial analysis showed heterogeneous distribution, with most municipalities reporting no cases and higher prevalence and mortality concentrated in few areas. Conclusion: In this middle-income setting, isolated gastroschisis showed stable but higher prevalence and neonatal mortality than in high-income countries. The heterogeneous spatial pattern suggests regional disparities in risk and outcomes, highlighting the need for targeted public health strategies and further research on gastroschisis epidemiology.