Syphilis has been making a comeback in the United States for years, but its impact on pregnant women and their unborn children has reached a particularly urgent level. According to data released by the U.S. Centers for Disease Control and Prevention in January 2026, the rate of maternal syphilis climbed 28% between 2022 and 2024, rising from just over 280 cases to nearly 360 cases per 100,000 births.
That increase doesn’t exist in isolation. Since 2015, congenital syphilis the term for syphilis passed from a mother to her fetus during pregnancy has surged by 700%. Researchers and public health experts describe the situation as the result of multiple overlapping crises, each reinforcing the other.
What’s behind the rise
Syphilis is caused by the bacteria Treponema pallidum and has been climbing steadily in the general U.S. population since 2000. A pivotal shift occurred around 2018, when the infection, which had primarily affected men who have sex with men, began spreading more broadly across the general population of both men and women. That widening reach made a rise in maternal syphilis almost inevitable.
Public health funding has not kept pace with the problem. Federal spending on sexually transmitted infections, excluding HIV, has remained flat at roughly $160 million per year for decades. When adjusted for inflation, that represents a 40% loss in real purchasing power. Proposed 2026 federal appropriations would consolidate HIV, STI and tuberculosis programs and cut a combined $70 million a move that experts warn could further weaken an already strained response.
The Covid-19 pandemic made things worse. Safety net clinics reduced hours and staff during the outbreak, limiting screening and treatment availability precisely when the infection was spreading. At the same time, behavioral shifts that began in the early 2000s when improved HIV treatments made the virus more manageable contributed to a gradual decline in safer sexual practices, increasing exposure risk across multiple STIs, including syphilis.
The role of stigma and access gaps
Stigma plays a quiet but significant role in driving undetected cases. Healthcare providers may skip syphilis screening for patients they assume are in long-term monogamous relationships, even though that assumption can be wrong. Patients, meanwhile, may not disclose risky sexual behaviors or may be unaware they have been exposed through a partner.
Access to prenatal care is another major barrier. One in four pregnant people in the United States does not receive prenatal care during the first trimester, the period when syphilis screening carries the greatest potential to prevent transmission to the fetus. Insurance delays are a specific obstacle: while pregnancy can qualify someone for Medicaid, the enrollment process can take months, and some clinics won’t schedule appointments until coverage is confirmed. By the time screening happens, the window for the most effective intervention has often passed. Published studies show that only 56% to 90% of pregnancies covered by Medicaid are screened for syphilis even once during the entire pregnancy.
How syphilis progresses and what it does to a fetus
Syphilis moves through four stages. In the primary stage, a painless sore appears at the site of exposure within days to weeks and often goes unnoticed. The secondary stage, occurring three to six months after exposure, brings flu like symptoms, swollen lymph nodes, weight loss and a non itching rash that can spread to the palms and soles. These symptoms resolve on their own but the infection remains active.
A latent phase follows, during which the bacteria stays in the body for years without obvious symptoms. Without treatment, between 40% and 60% of patients eventually progress to the tertiary stage, which can involve seizures, heart defects, dementia and other serious complications.
The bacteria can cross the placenta at any stage of infection, though transmission is most likely within the first year. Congenital syphilis can cause miscarriage, stillbirth, developmental delays, blindness, hearing loss, bone and teeth malformation, and heart defects. Some symptoms appear at birth, while others may not surface until a child is older than 2.
Treatment and prevention
Syphilis is treatable with antibiotics, most commonly a long acting penicillin injection though that specific formulation is currently in short supply. Non pregnant patients without neurological symptoms can be treated with a 14 to 28 day course of doxycycline instead.
Prevention begins with consistent condom use or confirmed STI negative status in mutually exclusive partnerships. Post exposure doxycycline, taken within 72 hours of potential exposure, can also reduce risk. For pregnant women specifically, universal screening at three points the first trimester, the third trimester and at delivery remains the most effective tool for catching and treating the infection before it reaches the fetus.
