Hospital-recorded congenital syphilis rates by maternal origin in a referral hospital in Quito, Ecuador, 2009–June 2024: a retrospective observational study

Background Congenital syphilis is preventable, yet gaps in prevention persist during pregnancy. In Ecuador, intensified migration highlights the need to examine differences by maternal country of origin. We evaluated the association between maternal origin and rates of hospital-recorded congenital syphilis, temporal patterns, and, exploratorily, prenatal visits among recorded cases. Methods Retrospective observational study used records from a tertiary referral hospital in Quito, Ecuador, from January 2009 through June 2024. Live-birth denominators by maternal origin came from the census, and cases were identified in the Perinatal Information System among hospitalized newborns. The primary analysis comprised 32 strata defined by calendar period and maternal origin and used Bayesian Poisson regression with a flexible temporal function and live births as an offset. The secondary analysis was restricted to recorded cases. Results Among 111,742 live births, 255 congenital syphilis cases were recorded: 219 (85.9%) among mothers of Ecuadorian origin and 36 (14.1%) among mothers of foreign origin. Births to mothers of foreign origin had a higher recorded-case rate (RR = 2.47; 95% CrI: 1.69–3.51). Rates followed a nonlinear pattern, peaking in this group in 2018. Among 250 cases in the exploratory analysis, the expected number of prenatal visits was lower with foreign maternal origin (MR = 0.797; 95% CrI: 0.654–0.963). Conclusions Births to mothers of foreign origin showed higher rates of hospital-recorded congenital syphilis and, among recorded cases, fewer expected prenatal visits. The temporal coincidence with migration trends is descriptive and does not establish that migration or irregular migration status explains these differences.