A Pregnant Woman Who is a Contact of a Man with Infectious Syphilis

Infection of the fetus is more likely to occur when the mother’s infection is in the early stage, as at this time considerable numbers of treponemes are present in the circulation. During the first year of infection in an untreated woman there is an 80–90% probability that the infection will be transmitted to the fetus. The chance of fetal infection declines rapidly after the second year of infection in the mother and becomes rare after the fourth year. In general, the greater the duration of syphilis in the mother, the less chance there is of the fetus being affected. If a mother with early-stage syphilis is not treated, 25–30% of fetuses die in utero; 25–30% die after birth; and of the infected survivors 40% develop late symptomatic syphilis.