The bacteria can enter the body through the vagina, mouth, or rectum. The bacteria can pass through other openings as well, such as a cut or break in the skin. If syphilis occurs during pregnancy and is not treated, the baby will probably get the disease. The mother's infected blood reaches the baby through the placenta. Some babies infected with syphilis are born prematurely.
Many infected babies have no symptoms at birth, but symptoms develop weeks or months later.
Some babies are dead at birth. All women have blood tests for syphilis at their first prenatal visit. If your health care provider thinks you may have syphilis, he or she will look for chancres on your skin and in your vagina, cervix, and rectum. If you have sores, scrapings from the sores will be examined under a microscope to look for bacteria. Diagnosis of a newborn with syphilis is based on a history of the mother having syphilis, an exam of the baby, blood tests, and possibly x-rays.