Outcomes of infants born to pregnant women with syphilis: a nationwide study in Korea

Background: Despite the expansion of antenatal syphilis screening programs, congenital syphilis (CS) remains a concern. Purpose: This study aimed to analyze the manifestation and progress of CS, including treatment and follow-up, based on a nationwide study. Methods: From the Korean National Health Insurance Service database, a total of 548 infants were examined for CS during their first year of life from 2013 to 2018. Neurosyphilis and complications were investigated using the International Classification of Diseases-10 codes. Results: The birth rate of infants from mothers with syphilis was 2.8 per 10,000 live births for 5 years, which is not indicative of a decreasing trend. Overall, 148 infants were proven or highly probable or possible of having CS with treatment for 10 days; 66 infants were possible or less likely of having CS with only 1-day treatment. Jaundice (56 %) was common, followed by hearing impairment (14 %), renal disease (8 %), and mental retardation (8 %). Fourteen cases of neurosyphilis occurred. Infants with complications, including mental retardation, eye involvement, hearing impairment, or renal disease, were significantly associated with neurosyphilis (OR 8.49, P < 0.0001). Of 250 patients who received treatment, 92.8 % were treated with one medication: benzathine penicillin was used in 73 % of patients. Only four patients were re-treated due to treatment failure. In addition to the treponemal test, fluorescent treponemal antibody-absorption was the most utilized tool for diagnosis and follow-up. Conclusions: Establishing standardized guidelines for the evaluation of CS, as well as the establishment of treatment regimens and follow up-plans for the disease, at a national level would help improve maternal and neonatal care and facilitate the eradication of CS in Korea.