- In recent years there has been an increase in infants being born with syphilis in Canada
- Early syphilis screening followed by rapid initiation of treatment helps protect the fetus
- A large study of pregnancies in Ontario found that 20% did not receive timely syphilis screening
Rates of new syphilis diagnoses have been increasing over the past 20 years in high-income countries. In Canada, there is now an epidemic of syphilis. The initial symptoms of syphilis—a sore or chancre on or inside the genitals, mouth or other parts of the body—may be painless or go unnoticed. The germs that cause syphilis (called treponemes) quickly spread from the site of first contact. These germs can attack nerves in the ears (causing hearing loss) and eyes (causing loss of vision), and over time they can cause injury to vital organs, including the brain, bones, heart and circulatory system, liver and kidneys. Syphilis during pregnancy can harm the fetus. Symptoms of syphilis can mimic many other diseases. However, syphilis can be easily diagnosed with a simple blood test. Most people can recover with a single course of antibiotic therapy.
Congenital syphilis
In Canada, reports indicate that syphilis diagnoses are increasing in different populations, including women of reproductive age.
The increase in cases of syphilis has led to rising reports of infants with syphilis. Congenital syphilis can cause a range of problems, severely harming the fetus and resulting in stillbirth. Infants born with syphilis can develop a range of serious health issues, including blindness, loss of hearing and developmental problems.
Reports suggest that rates of congenital syphilis are also increasing in Australia, the United States, Portugal, Spain and other parts of Europe.
Preventing congenital syphilis
A critical part of preventing congenital syphilis is screening during the first three months of pregnancy. Early detection and treatment of syphilis during this stage of pregnancy are associated with a reduced risk for congenital syphilis.
A team of researchers in Ontario and Quebec reviewed health-related information collected from databases in Ontario. They focused specifically on syphilis screening at any time during pregnancy and during the birthing process.
In the period from January 2018 to December 2023, the researchers found data on 551,706 pregnancies. The average age at pregnancy in this study was 31.
Overall, 92% of women were screened for syphilis. However, the researchers found that 20% of women were not screened during the first trimester of pregnancy.
Results
In the present study, 92% of women were screened for syphilis at some point during pregnancy or delivery of the baby. The distribution of syphilis testing was as follows:
- first trimester – 86%
- second trimester – 12%
- third trimester – 2%
- during delivery – 0.6%
(Figures do not total 100 due to rounding).
Ideally, screening for syphilis during pregnancy should take place in the first trimester and then be repeated later in pregnancy. In the present study, only about 10% of pregnancies underwent syphilis screening more than once.
Researchers found that Northeastern Ontario had the highest proportion of pregnancies that were not screened for syphilis.
Understanding circumstances that affect access to care and syphilis screening
According to the research team, there are many factors that can make pregnant people vulnerable to syphilis and can raise barriers to accessing timely care. For instance, researchers stated that “pregnant people may be hesitant to disclose personal risk factors such as housing instability or substance use, because of experiences of stigma and fear of involvement of child protection services.” They added that “nonjudgmental and harm reduction approaches should be used when caring for pregnant people using substances; comprehensive care may require referring them to addictions counselling or community resources for psychosocial interventions and support.”
In cases where pregnant people have little or delayed access to prenatal care, the researchers advise that syphilis screening should be performed when an opportunity presents itself, such as in the following instances:
- during pregnancy testing
- during primary care or at walk-in clinics
- at sexual health centres
- at clinics that provide help for substance use disorder
- at clinics that provide mental health services
The researchers encourage consideration of point-of-care testing, as this can help lead to immediate treatment. They stated that such testing “may be appropriate for people at high risk of being lost to follow-up and should be considered in community-based settings (for example, harm reduction organizations, shelters) and outreach with unhoused populations.”
Missing people
The researchers used databases that collected information from people who had coverage under Ontario’s Health Insurance Plan (OHIP). People who did not have OHIP coverage at the start of the study or three years before conception occurred were excluded from the study.
The researchers subsequently did a separate analysis (a sensitivity analysis) of some of the excluded pregnancies. They found that pregnant people excluded from the main study were not likely to have screening for syphilis during pregnancy. The researchers stated that many of these people who were not screened “included those who were living in neighbourhoods with a high proportion of racialized people and newcomers. This population may face barriers in accessing or obtaining OHIP coverage, and even those with coverage may be less likely to access traditional prenatal care pathways because of factors such as socioeconomic status, cultural differences, language barriers, challenges in navigating the health care system, and fear of stigma or discrimination.”
Bear in mind
The researchers noted that “one in five pregnancies did not receive timely syphilis screening, indicating persistent gaps in coverage.” To bridge these gaps, the researchers called for low-barrier syphilis screening during pregnancy as well as access to immediate treatment when screening uncovers syphilis. They stated that “preventing congenital syphilis in the context of the increasing incidence of syphilis will require strengthening universal access to screening and implementation of innovative, equity-oriented public health interventions.”
—Sean R. Hosein
Resources
Sexually transmitted and blood-borne infections: Guides for health professionals – Public Health Agency of Canada
Winnipeg researchers warn about rising cases of syphilis-related stillbirths – CATIE News
Views from the front lines: Congenital syphilis – Prevention in Focus
Alberta study underscores the importance of syphilis testing in people who use stimulants – CATIE News
Early access to syphilis screening and treatment needed to prevent stillbirths – CATIE News
U.S. researchers encourage screening for neurological complications of syphilis – CATIE News
REFERENCES:
- Featherstone A, Willms H, Ospina MB, et al. Uptake of prenatal syphilis screening and its determinants in Ontario, Canada: a population-based retrospective cohort study. CMAJ. 2026 May 18;198(19):E725-E736.
- Moseley P, Bamford A, Eisen S, et al. Resurgence of congenital syphilis: new strategies against an old foe. Lancet Infectious Diseases. 2024 Jan;24(1):e24-e35.
- Lukehart SA. Chapter 187. Syphilis. In: Longo DL, Fauci AS, Kasper DL, Hauser SL, Jameson L, Loscalzo J, Holland SM, Langford CA. Harrison’s Principles of Internal Medicine, 22e New York, NY: McGraw-Hill; 2025.
- European Centre for Disease Control. Congenital syphilis – Annual Epidemiological Report for 2024. 21 May 2026. Available at: https://www.ecdc.europa.eu/en/publications-data/congenital-syphilis-annual-epidemiological-report-2024