A study of pregnant people with syphilis found that substance use during pregnancy was nearly twice as common among those who delivered an infant with congenital syphilis than among peers who did not pass the infection to their baby.

Prenatal syphilis screening is universally recommended in the United States and even required by law in some states, according to the CDC. Despite this, the incidence of syphilis has continued to increase, likely as a result of multiple factors, including limited access to care and substance use, according to previous findings.

In the new study, which was published in MMWR, researchers analyzed data on births that occurred from Jan. 1, 2018, to Dec. 31, 2021, in Arizona and Georgia to examine the prevalence of substance use among pregnant persons with syphilis by congenital syphilis pregnancy outcome, which they defined as “delivery of a stillborn or live-born infant meeting the surveillance case definition for probable or confirmed congenital syphilis.”

They also examined how often pregnant people with syphilis used substances such as tobacco, alcohol, cannabis, illicit opioids or other illicit, nonprescription substances.

They found that pregnant patients with a congenital syphilis outcome were nearly twice as likely to have used a substance during pregnancy as those without one, 48.1% vs. 24.6% (prevalence ratio = 1.95; 95% CI, 1.6-2.38).

Among pregnant people who used substances and delivered an infant with congenital syphilis, 38.2% did not receive prenatal care at all and 53.2% were not treated for syphilis during pregnancy, according to the report. Additionally, more than one-quarter (26.6%) were either incarcerated or experienced homelessness during pregnancy.
said syphilis screening and treatment should be addressed at every health care encounter for people who are pregnant, especially for pregnant people who use substances and those outside of traditional health care, such as jails, prisons and facilities providing services for people experiencing homelessness. They said “innovative approaches are needed to increase screening and treatment for syphilis among pregnant people who use substances, including expansion of screening and treatment to settings outside of prenatal care.”

“Although screening and treatment can prevent most cases of congenital syphilis, numerous barriers to implementing these prevention strategies exist, some of which might be amplified among persons who use substances,” they wrote. “Tailored interventions need to address barriers and facilitators for accessing screening and treatment for syphilis for persons with current or previous substance use, including those with a history of incarceration and homelessness.”