Study finds critical gaps in prenatal syphilis screening in Ontario

Congenital syphilis is entirely preventable-yet new research shows critical gaps in prenatal screening that are leaving some infants at risk. With funding from the Canadian Institutes of Health Research (Institute of Population and Public Health), researchers from ICES and Queen's University found that one in five pregnancies in Ontario did not receive syphilis screening in the first trimester. Furthermore, delayed screening was more common among equity-deserving populations. 

The study included 551,706 pregnancies from January 2018 to December 2023 and found that 507,169 were screened for syphilis, 435,162 of which were screened in the first trimester. While most pregnancies included in the study underwent syphilis screening, approximately three per cent of these pregnancies were screened late (in the third trimester or at delivery). 

In Canada, the rate of congenital syphilis in 2023 was 14.5 cases per 100,000 live births-an increase of 220 per cent since 2018-indicating an evolving epidemiology of infectious syphilis among women. As untreated congenital syphilis can lead to severe outcomes, including infant death, these trends underscore the importance of prenatal screening as a key preventive strategy. 

Congenital syphilis should not be happening in a high-income country with universal healthcare. When one in five pregnancies are not screened on time, it signals that our current systems are not reaching everyone equitably." 

Dr. Sahar Saeed, Assistant Professor in the Department of Public Health Sciences at Queen's University and senior author

These findings highlight an urgent need to rethink how screening is delivered. "Relying solely on traditional prenatal care models may not be sufficient to reach populations who face barriers to accessing care," says Amanda Featherstone, lead author of the study. "Providing non-judgemental, comprehensive care in tandem with complementary strategies, such as opportunistic screening and community-based outreach programs with the use of point-of-care testing, is a critical next step." These approaches have shown promise in reaching underserved populations and closing access gaps. 

The study "Uptake of prenatal syphilis screening and its determinants in Ontario, Canada: a population-based retrospective cohort study" is in the May issue of CMAJ. 

This work was supported by a Canadian Institutes of Health Research Catalyst Grant (STBBI Research in Canada: Beyond HIV/AIDS and Hepatitis C) (no. SR7 - 196517).