Gaps in the elimination of congenital syphilis in a tertiary care center in Thailand

Background The World Health Organization has set a goal to eliminate mother-to-child transmission of syphilis to a target of <50 cases per 100 000 live births. This study aimed to determine the rate of congenital syphilis and identify gaps in prevention. Methods A retrospective chart review was conducted in a tertiary care center in Bangkok, Thailand. The study included all pregnant women with positive syphilis serology and their infants. All congenital syphilis cases were categorized according to Centers for Disease Control criteria. Results From 2013 to 2017, 69 syphilis-infected pregnant women were included, with 30 congenital syphilis cases. The rate of congenital syphilis was 115 cases (95% CI 78-164) per 100 000 live births. The median (interquartile range) maternal age was 21 (18-32) years and 12 (17%) women had human immunodeficiency virus co-infection. Regarding maternal treatment, 28 (41%) women had inadequate treatment due to 13 cases (19%) of late or no antenatal care, six cases (8%) of recent infection near delivery, five cases (7%) of failure of treatment provision, and four (6%) others. There were three syphilitic stillbirths who were prematurely born to untreated pregnant women and 67 live births (one set of twins) of which 27 met definitions of probable congenital syphilis. They received complete treatment with penicillin and had non-reactive rapid plasma reagin within the first 6 months of life, with the exception of one who had non-reactive rapid plasma reagin at the age of 7 months. Conclusions Congenital syphilis remains a problem in our setting. Nearly half of pregnant women who had syphilis had inadequate treatment. There is an urgent need to strengthen diagnosis and the treatment cascade of syphilis during antenatal care.