Prenatal and congenital syphilis in British Columbia

To describe the incidence of maternal syphilis and the corresponding rate of infection in exposed neonates in British Columbia before and after a serious outbreak of infectious syphilis in the heterosexual population.

We conducted a retrospective chart review of pregnant women with positive syphilis serology and reported cases of congenital syphilis in British Columbia from 1994 to 2003. Clinical charts were reviewed for demographic information, staging of maternal syphilis, and stage of pregnancy when treatment was received. The primary outcome measure was the number of cases of congenital syphilis. We conducted a 2-sided z-test and Fisher's exact test to determine differences in the proportion of infectious syphilis in mothers and the number of cases of congenital syphilis before and during the major outbreak.

In 389 478 live births in British Columbia between 1994 and 2003, 77% of mothers had prenatal syphilis serology. A diagnosis of syphilis was made in 183 mothers, resulting in 5 cases of congenital syphilis. Four of these were in infants whose mothers did not undergo prenatal syphilis testing. The proportion of pregnant women with infectious syphilis was significantly higher after the onset of a major outbreak of syphilis in the community than it was before (P = 0.001), but there was no significant difference in the number of cases of congenital syphilis (3 before and 2 after the outbreak, P = 0.36).

Although syphilis rates in British Columbia during the study period rose steadily, the prevalence of congenital syphilis remained low. Our findings suggest that, in the context of a major outbreak, universal screening and prenatal syphilis testing may contribute to controlling rates of congenital syphilis.