Managing syphilis during pregnancy — practice tip

Authors

Rohit Vijh, MD MPH CCFP (biography and disclosures)
Disclosures: Board Member Vancouver Division of Family Practice Locuum Family Physician, Mid Main Community Health Centre CBT Skills Physician Facilitator, CBT Skills STI Sessional Physician, BCCDC Public Health and Preventive Medicine Resident, UBC PGME Clinical Instructor, Department of Family Practice, Faculty of Medicine, UBC (receive payments for teaching UGME/PGME students). Mitigating potential bias: Recommendations are consistent with published guidelines (BCCDC, PHAC, Perinatal Services BC) Recommendations are consistent with current practice patterns Treatments or recommendations in this article are unrelated to products/services/treatments involved in disclosure statements.

Jason Wong, MD MPH CCFP FRCPC (biography, no disclosures)

What care gaps or frequently asked questions have we noticed?

Many clinicians consider syphilis to be an uncommon condition in BC. However, infectious syphilis rates are climbing in BC and syphilis has re-emerged as a public health threat. While the syphilis epidemic in BC has been ongoing since 2015, the epidemiology of syphilis in BC has recently changed. Previously, most infectious syphilis cases were among gay, bisexual, and other men who have sex with men (gbMSM). However, in 2022, for the first time in over a decade, the majority of infectious syphilis cases diagnosed in BC are among heterosexual individuals, raising concerns of increases in congenital syphilis.

Data that answers these questions or gaps

Nationally, the number of infectious syphilis cases for females has increased by 729% from 2017–2021.¹ Likewise, in BC infectious syphilis among females and heterosexual individuals has been increasing dramatically.² From 2015 to 2022, infectious syphilis cases among females have increased nineteen-fold, from 28 to 545 cases, respectively; proportionally, infectious cases among females have increased from less than 4% in 2015 to 28% in 2022 of all infectious syphilis cases reported in BC.² Similarly, the proportion of infectious syphilis cases among heterosexual individuals increased nineteen-fold, from less than 3% in 2015 to 57% in 2022. Of the infectious syphilis cases diagnosed among females in 2022, over 90% occurred among females in child-bearing years (15–49 years old) and 5% were diagnosed during the prenatal period.²

These increases in syphilis among females have raised concerns of congenital syphilis. Congenital syphilis is a severe, often debilitating, and potentially lethal infection that is the result of in-utero transmission of syphilis. In Canada, the number of early congenital syphilis cases has increased rapidly from 4 cases in 2016 to 96 cases in 2021.¹ BC reported its first cases of early congenital syphilis in 2019 after having zero cases between 2014 and 2018.²

In response to the congenital syphilis case in BC as well as increasing cases of infectious syphilis among females, the Provincial Health Officer declared a provincial syphilis outbreak in 2019. As part of the outbreak response, universal screening for syphilis was recommended for all pregnant individuals in BC at the time of delivery, in addition to the recommendation for a syphilis screen in the first trimester or first prenatal visit.³

Provincial surveillance data found that there were 19 cases of infectious syphilis diagnosed at delivery since universal screening at delivery was implemented in October 2019 until the end of September 2022. Eleven (58%) of these maternal syphilis cases did not have another syphilis test during the current pregnancy while the remaining 8 (42%) had a previous non-reactive test during the current pregnancy. During the same period, there were 11 early congenital syphilis cases reported. Three resulted in stillbirth or neonatal loss. The delivering parent of 6 of these 11 early congenital syphilis cases had no or limited access to prenatal care while the other 5 had a previous negative screen for syphilis in the first or second trimester. These data suggest that universal screening at delivery is identifying individuals infected with syphilis who may not have been identified with risk-based screening alone. In fact, over 10% of individuals who had a syphilis screen at delivery did not have evidence of another syphilis screen in that current pregnancy.

A chart review of all female infectious syphilis cases in BC from March 2018 to 2020 was conducted to better understand the risk factors and drivers of syphilis and identify opportunities for prevention. Most cases had experiences with housing instability, substance use, and mental illness among those who reported concurrent conditions. Similar risk factors were found among cases diagnosed during pregnancy.⁴ These findings reinforce the importance of upstream social and structural factors as drivers of syphilis. Thus, there is a need to consider these concurrent factors to support overall health and well-being of people infected with syphilis.

What we recommend (practice tip)

Pregnant persons should be screened for syphilis during the first trimester (or first prenatal visit), and at delivery (or any time after week 35 for those planning home births) in BC.^3,5 Pregnant persons with ongoing risk for syphilis infection, such as new sexual partner(s), transactional sex, illicit drug use, or unstable housing, should also be screened for syphilis at 28–32 weeks of pregnancy.⁵ From March 2018 to 2020, 90% of the maternal syphilis cases in BC were classified as early latent, which is the asymptomatic stage of syphilis.⁴ This finding underscores the importance of screening to identify syphilis. Furthermore, given that primary syphilis lesions are painless, and secondary syphilis presents in a myriad of ways — making a clinical diagnosis of syphilis often challenging. Therefore, maintain a high clinical suspicion for syphilis and inquire about risk factors for syphilis, such as new or multiple sexual partners.

People delivering a stillborn infant after 20 weeks gestation should be tested for syphilis as well.⁵ For stillbirths, clinical specimens (e.g., placenta, umbilical cord blood) should be sent for syphilis testing to confirm the congenital syphilis diagnosis. Additional investigations may be indicated. Clinicians are available for consultation (see below).

Intramuscular benzathine penicillin G 2.4 million units in a single dose (administered into a divided dose of 1.2 million units given IM into each hip/buttock at the same visit) is the recommended treatment for infectious syphilis, including in pregnant individuals.⁶ Additional doses may be required depending on the duration of the infection.⁶ There is no satisfactory alternative to penicillin for the treatment of syphilis in pregnancy as the recommended alternate treatment with doxycycline is contraindicated during pregnancy.⁶

As a result,  we recommend penicillin desensitization followed by treatment with penicillin. Health-care providers can utilize the Drop The Label penicillin allergy de-labelling tool to aid in their assessment and management of patients with suspected or proven penicillin allergy.

Infants with possible or confirmed congenital syphilis require treatment with aqueous crystalline penicillin G IV 100,000–150,000 units/kg/day, administered as 50,000 units/kg per dose every 12 hours during the first 7 days of life and every 8 hours thereafter for a total of 10 days.⁶

Physicians who have questions about syphilis screening or treatment can contact the BCCDC public health nurse at 604-707-5607 or physician at 604-707-5610. Physicians can also speak with a clinician at Oak Tree Clinic directly for urgent referrals.

References

1. Public Health Agency of Canada. Infectious syphilis and congenital syphilis in Canada, 2021 (infographic). Accessed May 17, 2023. (View)
2. BC Centre for Disease Control. British Columbia Syphilis Quarterly Indicators 2022Q4 Report. (View)
3. Perinatal Services BC. New recommendations for syphilis screening in pregnancy. Updated September 3, 2019. Accessed May 17, 2023. (View).
4. Willemsma K, Barton L, Stimpson R, et al. Characterizing female infectious syphilis cases in British Columbia to identify opportunities for optimization of care. Can Commun Dis Rep. 2022;48(2-3):68-75. Published 2022 Feb 24. doi:10.14745/ccdr.v48i23a03 (View)
5. Public Health Agency of Canada. Syphilis guide: Screening and diagnostic testing. Updated 2022. May 17, 2023. (View).
6. BC Centre for Disease Control. British Columbia treatment guidelines: Sexually transmitted infections in adolescents and adults 2014. May 17, 2023. (View).

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