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Cases of congenital syphilis reached a 20-year high last year after they more than doubled from 362 in 2013 to 918 in 2017, leading health authorities to emphasize the importance of testing all pregnant women.

Congenital syphilis cases occur when a mother passes the bacteria to her baby during pregnancy or delivery and can cause a host of complications, including stillbirth, premature birth, and the death of the newborn. Babies who are born with syphilis can have neurological problems and may go blind or deaf within the first few years of their lives.


The new data, released Tuesday by the Centers for Disease Control and Prevention, reflect the increase in syphilis rates among women of childbearing age. But syphilis remains treatable with penicillin, which is why health authorities are stressing their recommendation that pregnant women get tested for syphilis at their first prenatal appointment.

“Really the key is trying to identify infected women as early as possible in their pregnancies and treat them without any delays,” said Dr. Sarah Kidd, a medical officer in the CDC’s Division of STD Prevention.

Thirty-seven states reported at least one case last year, with Louisiana, Nevada, California, Texas, Florida, Arizona, and Maryland all with rates higher than the national average.


Transmission of the disease from mom to baby can happen either when the mom is already infected when she gets pregnant or when she contracts the bacteria while pregnant. Health authorities recommend that women at high risk for the disease or those who live in places where syphilis is more common get tested again early in their third trimester and at the time of delivery.

About one-third of women who delivered a baby with syphilis in 2016 were tested during their pregnancy, but they either got infected after being tested or were not treated in time to prevent the disease from affecting the baby.

Treating the pregnant woman with penicillin will also treat the unborn child, but it cannot reverse any damage that has already occurred.

One challenge, Kidd said, is that many doctors do not have much experience recognizing syphilis, which has similar symptoms to other diseases and circulated at such low rates in the early 2000s that medical training programs did not highlight it.

Clinicians “need to be aware that syphilis is back,” Kidd said.

If left untreated, syphilis will be transmitted from mom to baby in about 80 percent of pregnancies, health officials say. Up to 40 percent of untreated cases will end in a stillbirth or the baby dying.