Congenital syphilis occurs when a mother's syphilis goes untreated during pregnancy and is passed to the baby through the placenta. A baby can also become infected with syphilis during labor or delivery.

The risk of infecting the baby is greatest when the mother is in the early stages of syphilis; however, infection is possible any time during pregnancy.¹

It is very important that a pregnant woman have a lab test to detect syphilis. The baby's risk of getting syphilis is significantly reduced if the mother receives treatment during pregnancy. If the mother is treated before the 16th week of her pregnancy, the baby will usually not become infected. Treating a pregnant woman in the secondary stage of syphilis before her last month of pregnancy reduces the chances the baby will be born with congenital syphilis by 98%. ²

If an infected mother does not receive treatment, the mother may miscarry, or the baby may be born dead, die shortly after birth, be born early, or be infected with syphilis.¹

Complications that can occur in a baby whose infected mother was not treated include:

• A flat bridge of the nose (saddle nose).
• Permanent incisor teeth that are peg-shaped, widely spaced, and notched at the end with a crescent-shaped deformity in the center (notched teeth or Hutchinson's teeth).
• Inflammation of the cornea, which may cause blindness (interstitial keratitis).
• A progressive, disabling, and life-threatening complication involving the brain (neurosyphilis).
• Deafness.
• Bone deformities.

Antibiotics can prevent progression of the disease in an infected baby. However, problems that have already developed may not be reversible.

If a baby with syphilis is not treated, the disease can progress to a late congenital stage, if the baby lives past the first 6 to 12 months.