Syphilis

Syphilis remains a major public health problem, and rates of reported syphilis infections have increased in both men and women almost every year since 2001. In pregnancy, the immune response to syphilis infection is blunted, and clinical symptoms may be subtle or absent. When present, the initial manifestation of the immune reaction is the primary chancre, which appears approximately three weeks after infection. Unlike in adults, initial infection in the fetus is systemic rather than localized. Intrauterine infection results from transplacental and then hematogenous spread of Treponema pallidum, occurring in 50–80% of pregnancies with untreated primary, secondary, or early latent syphilis and 10% of those with late latent syphilis. As part of the initial evaluation of a pregnant woman with syphilis, a detailed ultrasound evaluation may be performed to document whether characteristics of congenital infection are present, which suggest severe fetal infection.