Increase in Incidence of Congenital Syphilis — United States, 2012–2014

Virginia Bowen, PhD; John Su, MD, PhD; Elizabeth Torrone, PhD; Sarah Kidd, MD; Hillard Weinstock, MD


Morbidity and Mortality Weekly Report. 2015;64(44):1241-1245. 

In This Article


The rate of CS in the United States reached a low of 8.4 cases per 100,000 live births in 2012, after 4 years of steady decline. However, during 2012–2014, the national CS rate increased 38%. This rapid increase in the CS rate coincided with a 22% national increase in the rate of P&S syphilis among women during the same period.

In the United States, a case of CS is a sentinel event reflecting numerous missed opportunities for prevention within public health and health care systems.[7] There are two major opportunities to prevent CS: primary prevention of syphilis among women of reproductive age and men who have sex with women, and prevention of mother-to-infant transmission among pregnant women already infected with syphilis.

Preventing syphilis among women and their male partners requires that sexually transmitted diseases (STD) prevention programs quickly identify and respond to increases in syphilis cases among women and men who have sex with women in their jurisdictions. CS cases and cases of syphilis among women should be reported to the local health department within 24 hours of diagnosis, and STD programs should review local syphilis case data each week to detect increases in CS cases or cases of syphilis among women. In addition, CS cases should be reported to CDC within 1 month of diagnosis. STD programs should prioritize cases of infectious syphilis among women of reproductive age and their male sex partners for case investigation and partner services to reduce transmission and infection in these populations. STD programs might also consider enhancing surveillance efforts by determining pregnancy status on all reported syphilis cases in women and by monitoring the screening and treatment practices among prenatal care providers in communities at highest risk for delivering an infant with CS.

Mother-to-infant transmission of syphilis can be prevented or mother-to-infant transmission that has already occurred can be treated when maternal syphilis is detected, and benzathine penicillin G appropriate for the mother's stage of infection is initiated ≥30 days before delivery.[3] CDC recommends that all pregnant women be screened for syphilis at their first prenatal visit.[3] Women at increased risk for syphilis and women living in high-morbidity geographic areas should also be screened at the beginning of their third trimester and again at delivery.** When access to prenatal care is not optimal, rapid plasma reagin screening should be performed at the time that a pregnancy is confirmed (performed onsite by using a rapid plasma reagin card test, if possible, and the woman treated as necessary). Newborn infants should not be discharged from the hospital unless the syphilis serologic status of the mother has been determined at least one time during pregnancy and preferably again at delivery if the mother is determined to be at increased risk. Any woman who delivers a stillborn infant should be tested for syphilis.

A substantial percentage of CS cases are attributable to a lack of prenatal care; even among those receiving some prenatal care, the detection and treatment of maternal syphilis often occurs too late to prevent CS. Health departments, in partnership with prenatal care providers and other local organizations, should work together to address barriers to obtaining early and adequate prenatal care for the majority of vulnerable pregnant women. Women who are uninsured or underinsured and women with substance use issues have been found to be at increased risk for receiving inadequate or no prenatal care, placing them at increased risk for CS.[8,9]

The findings in this report are subject to at least three limitations. First, shortcomings in screening practices (e.g., inconsistent syphilis testing of mothers with stillborn infants) or underreporting can lead to missed cases.[10] Second, this analysis only stratified data at the regional and state levels; the observations reported here might not reflect more local (e.g., county- or city-level) epidemiology. Third, the use of 2013 natality data in the calculation of CS rates might overestimate the rate of CS by a limited amount; preliminary data indicate that births might have increased slightly in the United States during 2013–2014.

Although the United States experienced an overall decline in the rate of CS during 2008–2012, the rate increased substantially during 2012–2014, to the highest level since 2001. Racial and ethnic disparities persist, and CS prevention in the public health and health care sectors remains paramount. Addressing CS will depend upon health care providers and STD programs being aware of infectious syphilis among women of reproductive age and men who have sex with women in their jurisdictions; reporting cases of CS and cases of syphilis among women of reproductive age and men who have sex with women in a timely fashion; prioritizing STD partner services for syphilis cases among women of reproductive age and their sex partners; instituting more thorough prenatal screening practices when warranted; ensuring timely treatment of identified cases with benzathine penicillin G; and removing the barriers to timely and high quality prenatal care.

For mothers with primary, secondary, or early latent syphilis, a single intramuscular dose of 2.4 million units of benzathine penicillin G; for mothers with late latent syphilis, 7.2 million units of benzathine penicillin G, administered as 3 intramuscular doses of 2.4 million units each at one-week intervals.
**Information about the incidence of syphilis among women is available at the state- and county-level through the National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention Atlas and is available at