Data released last week by the Centers for Disease Control and Prevention shows a troubling trend: a sharp rise in the number of pregnant women diagnosed with syphilis, a sexually transmitted infection that, if left untreated, can cause serious harm to infants, including blindness.
While experts say the increase is tied in part to delayed prenatal care or none at all, maternal syphilis is not affecting all populations equally.
According to the CDC’s National Center for Health Statistics, the national rate of maternal syphilis more than tripled between 2016 and 2022. Early estimates show the numbers jumped another 28% in 2024. Rates among Black mothers increased 30%, while infections among white women rose 23%.
The largest increase occurred among American Indian and Alaska Native mothers, whose infection rate jumped 52%.
Researchers say a combination of improved testing and a true rise in infections across racial and ethnic groups is driving the surge.
How we got here
Maternal syphilis happens when several systems intended to protect pregnant women break down, experts say. Besides an absence of quality prenatal care, women are susceptible to the infection during pregnancy if they miss follow-up visits after a diagnosis as well as social vulnerability that affects every aspect of maternal healthcare.
“Delayed access to prenatal care was also associated with maternal syphilis, as more than one-third of the women [with infections] did not have a perinatal visit in the first trimester,” Dr. Robert L. Cook told JAMA Network Open in an article published last month.
Maternal syphilis occurs when systems designed to protect pregnant women break down, experts say. In addition to limited access to quality prenatal care, women are vulnerable if they miss follow-up visits after a diagnosis or face social and economic barriers that disrupt care.
“Delayed access to prenatal care was also associated with maternal syphilis, as more than one-third of the women [with infections] did not have a perinatal visit in the first trimester,” Dr. Robert L. Cook told JAMA Network Open in an article published last month.
The United States already has the highest maternal mortality rate among developed nations. Black women face the greatest risk. In 2023, their maternal death rate was three to four times that of white women, with the rate rising again in 2024.
While syphilis has not been directly linked to maternal deaths, the infection poses serious dangers for infants.
Congenital syphilis — when the disease is passed from mother to fetus — has surged nearly sevenfold between 2015 and 2024. Nearly 4,000 cases were reported in 2024 alone, the highest number in a single year since 1994, according to the CDC.
A plan that fell short
Speaking with JAMA, Cook noted that the medical and public health communities had put syphilis in its crosshairs, hoping to eradicate the infection. As part of that effort, many states required pregnant women to be screened early, testing them again during their third trimester and during labor and delivery.
But many states don’t require syphilis tests for pregnant women.
“Twenty years ago, the U.S. public health system confidently presented a plan to eliminate syphilis,” he said. But the plan, Cook said, has “not gone as intended, and pregnant women and their offspring are now bearing the brunt.”
Cook noted that other research found “syphilis rates among pregnant women in Mississippi “increased nearly 10-fold between 2018 and 2023.” Meanwhile, the overall infection rate and the rate for men have both decreased over the same time period.
In the early 2020s, most states began prescribing the antibiotic doxycycline to men who had an increased risk for the disease but hadn’t been infected, which may have protected them from it. But the drug is unsafe for pregnant women and isn’t recommended for women in general.
Meanwhile, the U.S. last year had a shortage of the only injectable antibiotic approved for treating syphilis in pregnant women.
Researchers say the rate of infection among pregnant women is rising because of barriers to prenatal care, economic insecurity, limited health insurance coverage, and systemic inequities that contribute to delayed or missed treatment. There’s also some concern that recent staffing and budget cuts at the CDC will limit the ability to track the epidemic’s spread and to hire the public health workers needed to reverse this trend.
Syphilis during pregnancy is treatable with antibiotics, which can prevent transmitting it to the fetus. Infected infants can face a host of adverse outcomes including brain and nerve disorders, low birthweight, preterm birth and fetal or neonatal death.
This story originally appeared here.