Gestational Syphilis in Santa Catarina: Temporal Analysis by Macro-Region Between 2013 and 2023

Syphilis is a systemic infection caused by Treponema pallidum, with a high degree of pathogenicity, which can be transmitted vertically during pregnancy and lead to unfavorable outcomes for mother and baby. To analyze the trend in gestational syphilis (GS) notifications in the state of Santa Catarina, Brazil, from 2013 to 2023. Ecological observational study based on public secondary data from the Notifiable Diseases Information System (SINAN) on the DataSUS platform – Ministry of Health, from 2013 to 2023. Incidence rates (per 1,000 live births) were analyzed by macro-region (South, Planalto Norte and Northeast, Greater Florianópolis, Foz do Rio Itajaí, Vale do Itajaí, Midwest, and Serra Catarinense), and variables included age group, race/skin color, schooling, and clinical classification. From 2013 to 2023, 20,589 GS cases were reported in Santa Catarina. Detection rates increased in all macro-regions, from 5.83 cases per 1,000 live births in 2013 to 30.08 in 2023, with a peak in 2022 (30.94). The Serra Catarinense macro-region had an overall rate of 34.9 in the period, with a marked peak in 2022 (63.02), followed by Greater Florianópolis, with a rate of 23.7 and a peak in 2022 (35.06), and Grande Oeste with 21.48 and a peak of 33.81 in 2023. The lowest rate was in Vale do Itajaí (12.44). In Santa Catarina during the period, 76.20% (n = 15,730) of cases occurred in women aged 20–39 years, and 20.87% (n = 4,309) in those aged 15–19 years. Regarding schooling, 26.7% (n = 5,507) had completed high school, 17.5% (n = 3,603) had incomplete 5th–8th grade of elementary school, and schooling was recorded as ignored in 17.9% (n = 3,686). As for race/skin color, 75.7% (n = 15,621) self-identified as white. Regarding clinical classification of GS infections, 46.4% (n = 9,573) were latent syphilis and 28.6% (n = 5,908) primary syphilis; however, 14.8% (n = 3,051) had this variable recorded as ignored. During the period analyzed, the highest GS rate was in the Serra Catarinense macro-region, followed by Greater Florianópolis, with the lowest rate in Vale do Itajaí. There was a predominance of young adult women with completed high school education, white race, and clinical diagnosis of latent GS.