Ontario Study Warns One in Five Pregnancies Miss Timely Syphilis Screening

A new Canadian study has revealed a concerning gap in prenatal care in Ontario, finding that one in five pregnancies did not receive timely syphilis screening, even though early diagnosis and treatment can prevent serious harm to newborns.

The study, published in the Canadian Medical Association Journal, examined health administrative data for more than 550,000 pregnancies in Ontario between 2018 and 2023. Researchers found that about 20 per cent did not receive screening at the recommended time, meaning in the first trimester or at the first prenatal care visit. More than 44,000 pregnant people were not tested with a blood test when screening should have occurred early.

Syphilis is a sexually transmitted infection that can pass from mother to baby during pregnancy or birth. If untreated, it can lead to miscarriage, stillbirth, preterm birth, developmental delays, blindness, deafness and even infant death. Public Health Ontario says prenatal testing can reduce the risk of transmission from an infected mother to an infant.

According to the study, 8 per cent of pregnant people were not screened at all, while 79 per cent were screened in the first trimester. Among those screened, about 3 per cent were tested late, either in the third trimester or at delivery.

Dr. Sahar Saeed, an assistant professor in the Department of Public Health Sciences at Queen’s University and a co-author of the study, said the findings show persistent gaps in coverage within a publicly funded health system. The researchers noted that late screening may be linked to barriers in access to early prenatal care, especially among marginalized communities.

The findings come as syphilis rates among females of reproductive age have risen sharply in recent years. The study notes that rates of infectious syphilis among females aged 15 to 39 increased over a decade from 2.3 to 53.8 cases per 100,000, while congenital syphilis rose from 0.3 to 14.5 cases per 100,000 live births.

The message is not to create fear, but to emphasize prevention. Syphilis can be treated with antibiotics, and the earlier it is diagnosed during pregnancy, the lower the risk of severe outcomes. Global News reported that treatment is typically one to three benzathine penicillin injections, depending on the stage of infection.

Researchers argue that traditional prenatal care alone may not be enough to reach all pregnant people, especially those facing barriers related to housing, income, language, access to providers or delayed care. They called for more flexible approaches, including opportunistic screening, community outreach and point-of-care testing.

For families in Ontario, the practical step is clear: at the start of pregnancy or the first visit with a doctor or midwife, ask whether syphilis screening has been completed as part of routine prenatal blood work, and whether repeat testing is needed later in pregnancy.