Congenital syphilis is an infection caused by Treponema pallidum, a spirochete bacterium, which affects multiple systems and presents important clinical outcomes when transmitted vertically. It represents one of the greatest challenges faced by public health in Brazil, due to the numerous negative repercussions on fetal and neonatal life. Among its main consequences are congenital malformations, growth and developmental delays, sensory and neurological alterations, systemic complications, and death. This study aimed to analyze the temporal trend of hospitalizations for congenital syphilis in the Southern Region of Brazil from 2014 to 2023.

An ecological time-series study was conducted using data from the Hospital Information System of the Unified Health System (SIH/SUS), recorded under ICD-10 code A50.9. Statistical analysis was performed using simple linear regression, stratified by sex, age group by sex, and state, considering statistical significance at p < 0.05.

A total of 18,487 hospitalizations of children aged 0 to 4 years were recorded in the Southern Region involving patients of both sexes. There was an increasing trend in the overall hospitalization rate for congenital syphilis in the Southern Region (p < 0.05), with a mean rate of 9.39 hospitalizations per 10,000 inhabitants. The same behavior was observed in Paraná, Santa Catarina, and Rio Grande do Sul, with mean rates of 4.85, 6.42, and 16.43 hospitalizations per 10,000 inhabitants, respectively. There was an increasing trend in both sexes. Regarding age group by sex, in females there was an increase in the <1 year age group (p < 0.05) and stability in the 1–4 years age group (p > 0.05). In contrast, among males, an increase was observed in both age groups analyzed (p < 0.05).

It is concluded that there was an overall and state-level increase in the trend of hospitalizations for congenital syphilis in the Southern Region from 2014 to 2023. This growth results from multiple factors, showing the positive contribution of increased testing and prenatal care policies to a concomitant increase in diagnoses. However, prenatal follow-up and adequate treatment remain factors to be improved in order to reduce both the incidence and hospitalization rates of congenital syphilis.