Congenital syphilis

Background

There has been an increase in the number of babies born with syphilis in the U.S. in recent years. Utah is no exception to this trend as there were 4 times as many congenital syphilis cases in 2023 compared with 2019. Fortunately, we can prevent congenital syphilis. Providers who care for pregnant patients are key partners in the fight against the rise in congenital syphilis. Information on testing, treatment, and follow up for pregnant patients and babies is listed below.

Screening pregnant patients

  • Utah law requires syphilis screening for all pregnant patients within 10 days of their first exam.
  • In 2024, the American College of Obstetricians and Gynecologists (ACOG) updated their recommendations to also screen all pregnant patients during the third trimester and again at delivery.
  • There are 2 algorithms for syphilis screening (see ACOG’s syphilis testing algorithm). Both algorithms are appropriate to use, but the reverse algorithm is better at detecting early and late latent infections.

Treating pregnant patients

  • Pregnant patients with syphilis must be treated with Bicillin based on their stage of infection.
  • Those with a penicillin allergy need to see a specialist to be desensitized and treated with Bicillin.
  • Treatment for pregnant patients must be started at least 30 days before delivery to prevent infection in their baby.
  • Regardless of stage, patients with neuro, ocular, or otic symptoms of syphilis should be treated with an IV penicillin course. See details in the 2021 CDC STI Treatment Guidelines.

Syphilis treatment by stage

Primary, secondary, and early latent

  • One intramuscular dose of 2.4 mu Bicillin

Late latent syphilis

  • Three weekly intramuscular doses of 2.4 mu Bicillin
  • These doses should 7 days apart, but up to 9 days is okay for pregnant patients. Pregnant patients who go more than 9 days between doses must restart treatment.

Follow-up testing during pregnancy

  • Coordinated prenatal care and documented treatment are important.
  • If a pregnant patient is treated at or before 24 weeks’ gestation, wait at least 8 weeks to repeat RPR testing unless they have new symptoms.
  • RPR testing should be repeated for all pregnant patients at delivery.
  • Post-treatment RPR titer response varies during pregnancy. Many patients do not have a fourfold decrease (e.g., 1:8 to 1:2) by delivery.
  • A fourfold increase (e.g., 1:4 to 1:16) could mean the patient was reinfected or has neurosyphilis. People with a fourfold increase in titer should be reevaluated and treated.

Past infections

  • If a pregnant patient has had syphilis in the past outside of Utah, work with your local health department to get their testing and treatment history.
  • Without proof of appropriate treatment, a pregnant patient must be treated again for the current stage of infection.
  • If a pregnant patient’s records are outside the U.S., they need to get their own records if possible. If these are not available, they will need to be treated again.
  • A baby born to a mother who tests positive for syphilis and does not have documented treatment should be managed as a congenital syphilis case.
A baby with light brown hair and a white onesie crawls on a carpet toward the camera.

Testing and treatment for babies

  • All babies born to mothers who tested positive for syphilis during pregnancy should be tested with an RPR and checked for symptoms of congenital syphilis.
  • The CDC guidelines list 4 different scenarios based on the mother’s testing and treatment. Each scenario gives evaluation and treatment recommendations for the baby.
  • Babies with a positive RPR test at birth should be tested every 2–3 months until the test becomes negative.
  • Babies with a negative RPR test at birth should be tested again at age 3 months.
  • Refer to the CDC guidelines for how to interpret and manage follow-up test results.