The rate of syphilis among pregnant women in the U.S. has more than tripled in recent years, according to new research that helps shed light on an even greater surge of babies born with the potentially deadly infection.
The U.S. rate of maternal syphilis cases rose 221.6%, from 87.2 infections per 100,000 births in 2016 to 280.4 per 100,000 in 2022, according to a new report released Tuesday by the Centers for Disease Control and Prevention’s National Center for Health Statistics. During the same time frame, the total number of annual cases rose from 3,431 to 10,232.
Maternal syphilis rates increased each year of the study period, ranging from a 15% rise from 2017 to 2018 to a 32% rise from 2021 to 2022.
Syphilis rates increased for mothers of all maternal age groups throughout the study period. The largest increase, of 290%, occurred among those under 20, rising from 107.3 per 100,000 births in 2016 to 418.6 per 100,000 in 2022.
Mothers between the ages of 30 and 34 experienced the second-largest percentage increase at 277%, followed by a 239% rise among mothers between the ages of 25 and 29, and a 226% increase in the infection rate among mothers between 20 and 24.
Maternal syphilis rates rose for all mothers regardless of when they began receiving care, though the study found the largest spike occurred among mothers reported to have had no prenatal care, at 298% from 2016 to 2022.
Transmitted through vaginal, anal or oral sex, early stages of syphilis usually result in sores and rashes on affected locations on the body. But if left untreated, syphilis can ultimately lead to more severe conditions such as organ failure, blindness and death.
An estimated 40% of babies born to mothers with untreated syphilis are stillborn or die from the infection as a newborn, according to the CDC.
Rates of maternal syphilis increased in 47 states and Washington, D.C., from 2016 to 2022, more than doubling for 40 states and the district. From 2021 to 2022, the rate of maternal syphilis ranged from a low of 45.8 cases per 100,000 births in Maine to a high of 762.6 per 100,000 in South Dakota.
Six states – New Mexico, Colorado, Mississippi, South Dakota, Montana and Alaska – saw the rate of maternal syphilis rise by more than 400% during the study period.