Syphilis in pregnancy: an ongoing public health threat

Global, regional, and national burden of syphilis, 1990-2021 and predictions by Bayesian age-period-cohort analysis: a systematic analysis for the global burden of disease study 2021

Objective

To comprehensively assess the global burden of syphilis and related risk factors over 1990-2021, forecast future disease trends, and understand the impact of syphilis on global health.

Methods

Global Burden of Disease Study 2021 (GBD 2021) data were used for age-, sex-, and region-stratified analysis of the numbers and age-standardized rates (per 100,000 population) of syphilis incidence, prevalence, deaths, and disability-adjusted life years (DALYs). Next, a differential analysis of syphilis risk factors was performed. Finally, trends for years after 2021 were predicted using Bayesian age-period-cohort (BAPC) prediction models.

Results

In 2021, the total number of syphilis prevalence globally was 70,541,482.80 (95% uncertainty interval: 54,910,897.66-88,207,651.97), with the highest numbers noted in Central Sub-Saharan Africa [4,622.60 (95% uncertainty interval: 3,591.97-5,753.45)]. Over 1990-2021, the global age-standardized prevalence and incidence rates increased, whereas the age-standardized death and DALY rates decreased. Among all groups, infants aged <5 years demonstrated the highest age-standardized DALY rates. Moreover, the lower the sociodemographic index (SDI), the higher was the age-standardized rate. The primary factor contributing to syphilis disease burden was identified to be unsafe sex. BAPC analysis revealed an overall increase in age-standardized prevalence rate in the <5-year age group over 1990-2035, and the highest age-standardized prevalence rate occurred in the 25-34-year age group.

Conclusion

Between 1990 and 2021, syphilis occurrence and prevalence increased consistently. Projections indicated a continual increase in syphilis incidence in children aged <5 years, and age-standardized prevalence rates were the highest in adults aged 25-34 years. Our results regarding the epidemiological trends of syphilis and its variations across regions, age groups, and sexes may aid policymakers in addressing the global impact of the disease effectively.

Lack of Serological Response by Delivery to Syphilis Treatment Does Not Impact Pregnancy Outcomes

Objectives: Maternal syphilis can lead to serious adverse pregnancy outcomes, including neonatal death. A 4-fold decline in blood non-treponemal titer at six months after the treatment of syphilis compared to the baseline is considered as an adequate serological response. However, the duration of normal human gestation does not allow the ascertainment of an adequate serological response. Aim: The aim of this study was to assess correlations between the lack of a 4-fold decrease in non-treponemal titer by delivery after syphilis treatment and fetal and newborns' condition and serological outcomes. Methods: Fourteen pregnant patients (gestational age 16-22 weeks) diagnosed with early syphilis (secondary or latent) were treated with intramuscular benzathine penicillin and subsequently monitored clinically, serologically, and ultrasonographically at monthly intervals. Based on the non-treponemal test results at delivery, patients were stratified into two groups: those with a 4-fold decline in titers and those without such a decline. All newborns were clinically and serologically assessed for congenital syphilis at birth and then monitored until serological tests became negative. Results: Fifty percent of the included women did not achieve a 4-fold decline in non-treponemal titer by delivery. Patients from the group showing a 4-fold decline in RPR titer at delivery and those without such a decline did not differ in basic demographic and clinical characteristics or in ultrasound parameters used for fetal assessment. Based on the clinical and laboratory assessments of newborns on the day of delivery and during a 6-month follow-up, none were diagnosed with congenital syphilis or required treatment for syphilis. Conclusions: The lack of an adequate serological response to syphilis therapy by delivery among patients treated between 16 and 22 weeks of pregnancy does not appear to be associated with adverse fetal and neonatal outcomes.

The Epidemic of Congenital Syphilis in the Indigenous and Rural Populations of South Dakota

From 2020 to 2023, South Dakota witnessed a substantial increase in cases of congenital syphilis (CS), with the highest rates identified in rural and Native American (NA) communities. Here, we discuss 3 severe cases of CS in premature infants born to NA individuals and communities in South Dakota with poor access to prenatal care. The infants in these 3 cases presented with varying clinical conditions, including respiratory failure, persistent pulmonary hypertension of the newborn, severe direct hyperbilirubinemia, feeding intolerance, and necrotizing enterocolitis. Lack of prenatal care and other systemic health disparities likely contributed to the increased disease burden. For NA communities, rurality, limited resources, systemic racism, historical trauma, and lack of trust in medical institutions likely contribute to inadequate prenatal care. All 3 of these cases also occurred in pregnant people with a present or history of substance use disorders, which may have led to further hesitancy to seek care because of fear of prosecution. To combat the rising number of syphilis and CS cases, we advocate for new and continued outreach that provides education about and testing for sexually transmitted diseases to NA and rural populations, increased care coordination, the integration of point-of-care testing and treatment strategies in lower resource centers, and legislative allocation of additional resources to engage pregnant people with or at risk for substance use disorders.

Syphilis Treatment Among People Who Are Pregnant in Six U.S. States, 2018-2021

OBJECTIVE

To describe syphilis treatment status and prenatal care among people with syphilis during pregnancy to identify missed opportunities for preventing congenital syphilis.

METHODS

Six jurisdictions that participated in SET-NET (Surveillance for Emerging Threats to Pregnant People and Infants Network) conducted enhanced surveillance among people with syphilis during pregnancy based on case investigations, medical records, and linkage of laboratory data with vital records. Unadjusted risk ratios (RRs) were used to compare demographic and clinical characteristics by syphilis stage (primary, secondary, or early latent vs late latent or unknown) and treatment status during pregnancy (adequate per the Centers for Disease Control and Prevention's "Sexually Transmitted Infections Treatment Guidelines, 2021" vs inadequate or not treated) and by prenatal care (timely: at least 30 days before pregnancy outcome; nontimely: less than 30 days before pregnancy outcome; and no prenatal care).

RESULTS

As of September 15, 2023, of 1,476 people with syphilis during pregnancy, 855 (57.9%) were adequately treated and 621 (42.1%) were inadequately treated or not treated. Eighty-two percent of the cohort received timely prenatal care. Although those with nontimely or no prenatal care were more likely to receive inadequate or no treatment (RR 2.50, 95% CI, 2.17-2.88 and RR 2.73, 95% CI, 2.47-3.02, respectively), 32.1% of those with timely prenatal care were inadequately or not treated. Those with reported substance use or a history of homelessness were nearly twice as likely to receive inadequate or no treatment (RR 2.04, 95% CI, 1.82-2.28 and RR 1.83, 95% CI, 1.58-2.13, respectively).

CONCLUSION

In this surveillance cohort, people without timely prenatal care had the highest risk for syphilis treatment inadequacy; however, almost a third of people who received timely prenatal care were not adequately treated. These findings underscore gaps in syphilis screening and treatment for pregnant people, especially those experiencing substance use and homelessness, and the need for systems-based interventions, such as treatment outside of traditional prenatal care settings.

Update on syphilis in pregnancy: marrying basic science advances and clinical perseverance to solve an ancient public health problem

PURPOSE OF REVIEW

While the clinical disease of syphilis, its consequences in pregnancy, and its sensitivity to penicillin treatment have remained relatively unchanged for a century or more, new technologies and basic discoveries in syphilis research have translated into tangible advances in clinical diagnosis, treatment, and prevention. The purpose of this review is to help the reader understand some of the recent relevant scientific publications on syphilis and its causative organism in a clinical obstetric context.

RECENT FINDINGS

Rates of adult and congenital syphilis have risen dramatically in the last decade despite public health efforts. Penicillin shortages and lack of screening or adequate treatment have all contributed to global disease burden. Advances in genomic and microbiological characterization of this spirochete have led to new developments in serologic and molecular diagnosis as well as evaluation of potential vaccine candidates. Until a syphilis vaccine is available, substance use disorders and lack of screening in pregnancy are associated with increased congenital syphilis, and these challenges will require novel solutions to fully address this public health crisis.

SUMMARY

Addressing the burden of congenital syphilis demands that obstetricians stay well informed of new tools and resources for diagnosis, treatment, and prevention of syphilis now and in the future.

Borrelia burgdorferi colonizes the mammary glands of lactating C3H mice: does not cause congenital Lyme disease

Transplacental transmission of syphilis causing spirochete, Treponema pallidum subspecies pallidum, from mother to child results in congenital syphilis, an ever-expanding devastating disease worldwide. Although adverse effects of untreated gestational Lyme disease, caused by a related spirochete, Borrelia burgdorferi on fetus viability and development have been observed, cases of congenital Lyme disease are not reported. In this study, we show that B. burgdorferi colonizes mammary glands of C3H mice only postpartum; however, neither transmission of these spirochetes from dams-to-pups occurs nor congenital Lyme disease is observed in pups.

A Rare Case of Neurosyphilis with Calvaria Osteitis Presenting in Pregnancy

Background

The incidence of syphilis throughout the world is increasing. Rates in pregnancy are similarly rising, presenting risks of an untreated syphilis infection that can be detrimental to the mother and fetus. Although routine screening for syphilis infections is recommended at the initial prenatal visit, there is a lack of universal agreement on rescreening pregnant people and approximately 50% of syphilis cases are asymptomatic in the general population. Furthermore, some symptoms of syphilis can overlap with nonspecific pregnancy-related symptoms. Meanwhile, Treponema pallidum can spread to various maternal and fetoplacental tissues quickly after infection and occur at any stage of syphilis.

Case

A 26-year-old gravida 5 para 2 presented with a new onset headache and visual and auditory changes at 23 weeks of gestation. A computerized tomography scan revealed numerous ill-defined lytic lesions throughout the calvarium, suspicious for syphilitic osteitis. She tested positive for syphilis antibodies with a rapid plasma reagin (RPR) titer of 1 : 32. Cerebrospinal fluid evaluation from a lumbar puncture resulted in reactive fluorescent treponemal antibody (FTA) testing. She was diagnosed with secondary syphilis with osteitis and neuro and otic components. She completed 14 days of intravenous aqueous crystalline penicillin G with additional benzathine penicillin G 2.4 million units intramuscular weekly for two weeks. There was no evidence of congenital syphilis on neonatal examination.

Conclusion

Syphilitic osteitis and neuro, otic, or ocular syphilis infections occur rarely in the nonpregnant population, and therefore, little data in pregnancy is available to inform outcomes in these specific disease states. It is of paramount importance to complete appropriate syphilis screening, recognize symptoms, and consider utilizing rescreen protocols to ensure prompt infection identification and treatment. For neuro, otic, and ocular syphilis, aqueous crystalline penicillin G (as opposed to benzathine penicillin G) is required to achieve treponemicidal concentrations in those physiologic compartments. There is no agreement as to the appropriate treatment regimen for the rare finding of syphilitic osteitis.

The Mortality of Congenital Syphilis

OBJECTIVES

To document the case-fatality rate (CFR) of congenital syphilis diagnosed by molecular tools and rabbit infectivity testing (RIT) of clinical specimens in addition to standard evaluation and to compare that with the CFR using the Centers for Disease Control and Prevention (CDC) surveillance case definition.

STUDY DESIGN

Prospective, single site, cohort study of all cases of syphilis among mothers and their infants from 1984 to 2002. The diagnosis of congenital syphilis was determined using IgM immunoblotting, polymerase chain reaction, and RIT of fetal or infant specimens in addition to clinical, laboratory, and radiographic criteria. Data were retrospectively reviewed to ascertain fetal and neonatal mortality.

RESULTS

During the 18-year study, there were 191 cases of congenital syphilis confirmed by abnormalities on clinical, laboratory, or radiographic evaluation and/or positive serum IgM immunoblot, blood polymerase chain reaction, or blood/cerebrospinal fluid RIT. Of the 191 cases, 59 died for a CFR of 31%. Of the 59 deaths, 53 (90%) were stillborn and 6 (10%) died in the neonatal period. The majority (74%, 39/53) of stillbirths occurred in the third trimester. The CDC surveillance case definition correctly identified all infants with congenital syphilis, but the CDC CFR was 10% which underestimated the CFR by more than 300%.

CONCLUSIONS

Our findings corroborate the high sensitivity of the CDC surveillance definition for congenital syphilis but highlight its poor estimation of its associated mortality. The CFR among infected progeny of pregnant women with syphilis was 31%, due mostly to demise in the third trimester and as such highlights the need for detection and appropriate treatment of syphilis during pregnancy.