Despite universal access to screening for
syphilis in all pregnant women in Canada, cases of
congenital syphilis have been reported in recent years in areas experiencing a resurgence of infectious
syphilis in heterosexual partnerships. Antenatal screening in the first trimester continues to be important and should be repeated at 28 to 32 weeks and again at delivery in women at high risk of acquiring
syphilis. The diagnosis of
congenital syphilis is complex and is based on a combination of maternal history and clinical and laboratory criteria in both mother and infant. Serologic tests for
syphilis remain important in the diagnosis of
congenital syphilis and are complicated by the passive transfer of maternal
antibodies which can affect the interpretation of reactive serologic tests in the infant. All infants born to mothers with reactive
syphilis tests should have nontreponemal tests (NTT) and treponemal tests (TT) performed in parallel with the mother's tests. A fourfold or higher titre in the NTT in the infant at delivery is strongly suggestive of congenital
infection but the absence of a fourfold or greater NTT titre does not exclude congenital
infection.
IgM tests for
syphilis are not currently available in Canada and are not recommended due to poor performance. Other evaluation in the newborn infant may include long bone radiographs and cerebrospinal fluid tests but all suspect cases should be managed in conjunction with
sexually transmitted infection and/or pediatric experts.