1 in 5 pregnant people in Ontario not screened properly for syphilis, new study says

TORONTO — A new study says one in five pregnant people in Ontario were not properly screened for syphilis, a preventable disease that can be fatal when passed from mother to baby.

The research, published in the Canadian Medical Association Journal, examined health administrative data for more than 550,000 pregnancies in the province between 2018 and 2023.

Sahar Saeed, a Queen’s University professor who co-authored the study, says data shows that more than 44,000 pregnant people were not screened for syphilis with a blood test when they should have been in the first trimester or at the initial prenatal visit.

Of those screened, more than 13,000 did so late, in the third trimester or at delivery.

Research shows that the sooner syphilis is diagnosed and treated in pregnancy, the less chance there is of adverse outcomes.

The consequences of missed or late screenings can include miscarriage, stillbirth, preterm birth, developmental delay, blindness and deafness.

She says the study found gaps in access to prenatal care were particularly pronounced in marginalized communities facing the greatest barriers.

The sexually transmitted infection is treated with one to three benzathine penicillin shots, depending on the stage of the illness.

This report by The Canadian Press was first published May 19, 2026.

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