Syphilis causes problems in 700,000 to 1.6 million pregnancies every year. Syphilis can cause a pregnant woman to have a miscarriage, a stillbirth, a premature baby, a baby with congenital syphilis, or a baby that dies before it is a month old. In sub-Saharan Africa, syphilis causes up to 20% of perinatal deaths (deaths that happen soon after a baby is born).