Against the backdrop of a near doubling in the incidence of congenital syphilis in the United States, the U.S. Preventive Services Task Force has reaffirmed its 2009 recommendation to screen all pregnant women for syphilis as early as possible in pregnancy.
The advice was the task force’s primary recommendation, based on a systematic review of seven studies and backed by the highest grade of evidence, in a statement published in JAMA. Untreated syphilis can be transmitted to the fetus at any time during pregnancy or birth, and congenital syphilis is associated with significant neonatal morbidity – including bone deformities and neurologic impairment – as well as stillbirth and neonatal death.
The prevalence of congenital syphilis was in decline from 2008 to 2012, but then increased by 87% from 2012 to 2016 – from 8.4 cases per 100,000 live births in 2012 to 15.7 cases in 2016. The increase coincided with rising national rates of syphilis among women of reproductive age – from 0.9 cases of primary and secondary syphilis infection per 100,000 women in 2012 to 1.9 cases in 2016.
Additionally, the task force recommended that pregnant women who had not received prenatal care be screened at delivery.
“Although nearly 70% of infants with congenital syphilis are born to mothers who received prenatal care, detection, and treatment of maternal syphilis often occurs too late to treat the fetus and prevent congenital syphilis,” wrote Susan J. Curry, PhD, from the University of Iowa, Iowa City, and her coauthors. “Recent data suggest that while screening rates for syphilis infection are generally high, the proportion of women screened earlier in pregnancy remains low (for example, 20% of women are screened only at the time of delivery).”
The review pointed to an observational study of the impact of the introduction of syphilis screening during pregnancy in China. That study of more than 2 million women showed that screening for syphilis in pregnancy increased from 89.8% of women in 2002 to 97.2% of women in 2012 and was associated with a decrease in the incidence of congenital syphilis from 109.3 cases to 9.4 cases per 100,000 live births.
The group found convincing evidence that screening reduced both the incidence of congenital syphilis and the risk of adverse outcomes related to maternal infection and that the potential harms of screening – such as false positives – were small.
The paper also referenced guidelines from the Centers for Disease Control and Prevention, the American Academy of Pediatrics, and the American College of Obstetricians and Gynecologists that high-risk women – such as those living in areas or communities with a higher prevalence of syphilis, women with HIV, or with a history of incarceration or sex work – should also be rescreened early in the third trimester and again at delivery. Similarly, women who are exposed to an infected partner also should be rescreened.
Further, the task force recommended screening for nonpregnant adolescents and adults at increased risk of syphilis infection.
In terms of treatment, the CDC currently recommends parenteral penicillin G benzathine as the treatment of choice for syphilis in pregnant women. However, the task force recommended clinicians consult the CDC website for updates.
The authors noted that no studies that met the inclusion criteria examined whether penicillin use during pregnancy was associated with any harm or looked at serious adverse events in women with a history of penicillin allergy.
“Because the review was primarily focused on screening, it did not address the efficacy of alternative antibiotic treatments [e.g., ceftriaxone] in pregnant women [with or without penicillin allergies],” the authors wrote.
The research was funded by the U.S. Department of Health and Human Services. No conflicts of interest were reported.