Abstract
Background
Congenital syphilis rates have risen nationally and in North Carolina (NC). We assessed syphilis screening among pregnant women in NC.
Methods
A retrospective chart review was conducted among patients with a pregnancy episode—created at first prenatal care encounter or labor/delivery—at a NC health system from 1/1/2019–12/31/2023. We estimated the proportion with syphilis screening at timepoints required by NC law (before 28 weeks of gestation, 28–31 weeks of gestation, and within 1 week of delivery) using syphilis test dates and delivery dates. We estimated prevalence ratios (PR) and 95% confidence intervals (CIs) using log binominal regression with generalized estimating equations to explore associations between clinical and sociodemographic factors and syphilis screening.
Results
We identified 64,803 pregnancies among 54,446 patients. Syphilis screening was conducted at least once in 99.5% of pregnancies. Only 27.6% had syphilis screening recorded at 28–31 weeks, and 22.0% had all required syphilis screening. Completion of required syphilis screening was more common among women aged 18–24 compared to ≥35 years (PR 1.15; CI: 1.10–1.21), and those who were uninsured compared to privately insured (PR 1.33; CI: 1.27–1.39), but less common among Black/African American women compared to White women (PR 0.93; CI: 0.89–0.96), those who preferred non-English languages for healthcare communication compared to English (PR 0.85; CI 0.81–0.90), and who initiated care in an emergency department compared to a women’s health clinic (PR 0.13; 95% CI: 0.12–0.15).
Conclusions
Completion of all required syphilis screening was low among pregnant women, highlighting a major gap in congenital syphilis prevention.
Keywords: Congenital syphilis, syphilis screening, pregnancy
Short Summary
The proportion of pregnant women screened for syphilis before 28 weeks of gestation, between 28–31 weeks of gestation, and at delivery was low in a North Carolina hospital system.
Introduction
Congenital syphilis (CS) has risen precipitously in the United States (US), with a 1,046% increase in reported cases from 2012 to 2024.2,3 North Carolina (NC) experienced a 1,297% increase in reported early syphilis cases among women of reproductive age and a 9,500% increase in CS cases from 2012 to 2024.4–6 Syphilis is associated with severe neonatal outcomes -- including stillbirth, preterm delivery, perinatal death, and congenital anomalies -- and health complications in pregnant women and their partners.7 Screening, diagnosis, and treatment of syphilis in early pregnancy can prevent CS, reduce maternal morbidity, and decrease community transmission.8
NC public health law has required universal syphilis screening for all pregnant women at the first prenatal visit, between 28–30 weeks of gestation, and at delivery since 1991.9 This law supports recommendations from the US Centers for Disease Control and Prevention (CDC) for screening of all pregnant women at the first prenatal visit, and at 28 weeks of gestation and delivery for women in communities with high rates of syphilis, living with HIV, or who are at high risk for syphilis.10 In 2021, CDC updated this recommendation to define high risk to include those who misuse drugs, have an STI during pregnancy, or have multiple sexual partners.8 The American College of Obstetrics and Gynecology (ACOG) endorses CDC guidelines, but as of 2024, also recommends universal syphilis screening during the third trimester and delivery in addition to syphilis screening for all pregnant individuals at the first prenatal visit.11 However, engaging pregnant women in syphilis screening is challenging. Limited access to care, housing instability, and comorbid mental health and/or substance use disorders have all been described as barriers to maternal syphilis screening.12 High CS rates suggest inadequate or delayed syphilis diagnosis and treatment among pregnant women, but data on syphilis screening in this population is limited. Notably, most prior studies assessing syphilis testing rates during pregnancy focus only on women who are diagnosed with syphilis or those who give birth to infants with CS,13–15 and specifically assess receipt of timely syphilis testing—defined as >30 days prior to delivery—rather than at the three timepoints recommended by ACOG and required by NC law.11
We sought to characterize the proportion of women in a large healthcare system in NC seeking pregnancy- or delivery-related care who complete syphilis screening at all required timepoints during pregnancy, and describe sociodemographic and clinical factors associated with engagement in the syphilis screening cascade.
Methods
Study setting and population
We conducted our study using data collected from a major state-owned, not-for-profit health system located in NC, with a large healthcare provider network, a university medical center, and 16 regional hospitals in over 20 additional locations throughout the state. The health system provides primary, acute, emergency, specialty, and tertiary care to patients in all of NC’s 100 counties. During the analysis period, all hospitals within the health system utilized a traditional syphilis screening algorithm, which began with a quantitative rapid plasma reagin (RPR) test followed by confirmatory reflex testing using a Treponema pallidum particle agglutination assay (TPPA).
Study design and variables
A retrospective chart review was conducted among patients with a pregnancy episode from 1/1/2019 through 12/31/2023. A pregnancy episode is created in the electronic medical record (EMR) at a patient’s first visit for prenatal care or at labor and delivery (if no prenatal care was received within the health system); each pregnancy episode corresponds to one unique pregnancy. However, unique patients may have had multiple pregnancies during the study period, and these pregnancies were included in the analysis. Patients were excluded from the analysis if they did not have both an estimated delivery date (EDD) and an actual delivery date recorded in the EMR; if the date of their last menstrual period (as calculated based on EDD) was more than 4 weeks before January 1, 2019; if their actual delivery date was after December 31, 2023 (to allow for sufficient follow up time); or if their pregnancy outcome was recorded as ectopic, molar, or abortion.
Sociodemographic data abstracted from the EMR included age, race, ethnicity, preferred language for healthcare communication, health insurance status, and ZIP code of residence. Medicaid and Medicare health insurance plans were categorized as public, while commercial, Tricare, and State Health Plan were all considered as private insurance. ZIP codes of residence were categorized as urban or rural using Rural-Urban Commuting Area (RUCA) Codes, with a primary RUCA score of 1–3 (metropolitan codes) classified as urban, and 4–10 (micropolitan, small town, and rural codes) classified as rural.16 Clinical data abstracted included EDD, actual delivery date, care setting at initiation of pregnancy episode (i.e., internal medicine clinic, family medicine clinic, emergency department), care setting affiliation (i.e. academic medical center, community hospital), pregnancy outcome, substance use status (including current or prior use), and test dates and results for HIV, Neisseria gonorrhoeae, Chlamydia trachomatis, and syphilis.
Syphilis testing dates, EDDs, and actual delivery dates were used to construct a syphilis screening cascade. Syphilis screening was recorded as occurring prior to 28 weeks of gestation, between 28–31 weeks of gestation, and within one week of delivery. Date of test results was used for syphilis test date due to incompleteness of data for test collection date. Date ranges captured syphilis testing over a slightly wider time range than required (i.e. within one week of delivery rather than only on the day of delivery) to account for delays in reporting of lab results and appointment scheduling, particularly during the COVID-19 pandemic.
This retrospective study was approved by the University of North Carolina Institutional Review Board, with a waiver of informed consent. Data collected contained protected health information and were accessed on encrypted computers and stored on a Health Insurance Portability and Accountability Act (HIPAA)-compliant storage platform.
Statistical analyses
Categorical variables were summarized using frequency counts and percentages. Continuous variables were summarized with medians and interquartile ranges. Prevalence ratios (PRs) and 95% confidence intervals (CIs) were estimated using log binomial regression to identify sociodemographic and clinical variables associated with engagement in the syphilis screening cascade. Generalized estimating equations (GEE) were used to account for clustering among women with multiple pregnancies. P values <0.05 were considered statistically significant. All analyses were performed with Stata version 19.0 (StataCorp, College Station, TX).
Results
During the five-year study period, 64,803 eligible pregnancies were identified among 54,446 unique patients across the NC health system. The median number of pregnancies per patient was 1 (range: 1–5). There were 9,549 patients (17.5%) who contributed more than one pregnancy over the five-year period.
Sociodemographic characteristics
Approximately half of pregnancies were among women <30 years of age, and 31.0% were among women aged 30–34 (Table 1). Most pregnancies were among White women (54.1%), with 22.8% among Black/African American women, and 18.8% among Hispanic/Latine women. Spanish was the preferred language for healthcare communication in 8.2%. Most pregnancies were among women who resided in urban ZIP codes (78.6%). Women had private health insurance in 55.1% of pregnancies, public health insurance in 34.6%, and were self-pay in 9.8%.
Table 1.
Sociodemographic characteristics of pregnant women by pregnancy in a North Carolina health system, 1/1/2019–12/31/2023 (N=64,803).
| Median | IQR | |
|---|---|---|
| Age (in years) | 29 | 25–33 |
| n | % | |
| Age (in years) | ||
| <18 | 819 | 1.3 |
| 18–24 | 13,884 | 21.4 |
| 25–29 | 17,983 | 27.8 |
| 30–34 | 20,093 | 31.0 |
| ≥35 | 12,024 | 18.6 |
| Race | ||
| American Indian/Alaska Native | 876 | 1.4 |
| Asian | 2,415 | 3.8 |
| Black/African American | 14,444 | 22.8 |
| Native Hawaiian/Pacific Islander | 124 | 0.2 |
| White | 34,279 | 54.1 |
| Other* | 11,247 | 17.7 |
| Missing** | 1,418 | |
| Ethnicity | ||
| Hispanic/Latine | 11,909 | 18.8 |
| Not Hispanic/Latine | 51,545 | 81.2 |
| Missing** | 1,349 | |
| Preferred language for healthcare communication | ||
| English | 58,283 | 90.4 |
| Spanish | 5,299 | 8.2 |
| Other | 915 | 1.4 |
| Missing** | 306 | |
| ZIP code of residence | ||
| Urban North Carolina*** | 50,950 | 78.6 |
| Rural North Carolina*** | 12,865 | 19.9 |
| Out of state | 987 | 1.5 |
| Missing | 1 | |
| Health insurance | ||
| Private | 35,729 | 55.1 |
| Public | 22,422 | 34.6 |
| Self-pay | 6,377 | 9.8 |
| Other | 275 | 0.4 |
Abbreviations: IQR, interquartile range.
Of those who identified as “other” race, 81.9% (9,215) identified as Hispanic/Latine ethnicity.
Missing excluded from denominator of proportions.
ZIP codes of residence were categorized as urban or rural using the United States Department of Agriculture’s Rural-Urban Commuting Area (RUCA) Codes, with a primary RUCA score of 1–3 classified as urban, and 4–10 classified as rural.
Clinical characteristics
Among pregnancies across the health system, the initial presentation was at an obstetrics/gynecology (OB/GYN) or women’s health clinic in 40.4%, an inpatient OB/GYN service or labor and delivery unit in 38.9%, and the emergency department in 8.2% (Table 2). Initial presentation for pregnancy- or delivery-related care in the health system occurred in the first or second trimesters in 52.2% and in the third trimester in 47.8% of pregnancies. Current substance use was reported in 6.2% of pregnancies. Most pregnancies included testing for HIV (82.4%), N. gonorrhoeae (71.7%), and C. trachomatis (72.1%). Positive HIV screening tests or viral loads were noted in 0.1% of pregnancies, positive N. gonorrhoeae tests in 0.5%, and positive C. trachomatis tests in 2.3%.
Table 2.
Clinical characteristics of pregnant women by pregnancy in a North Carolina health system, 1/1/2019–12/31/2023 (N=64,803).
| n | % | |
|---|---|---|
| Setting at initial presentation | ||
| Family medicine, internal medicine, or primary care clinic | 1,212 | 1.9 |
| Obstetrics/gynecology or women’s health clinic | 26,152 | 40.4 |
| Health department | 438 | 0.7 |
| Emergency department | 5,334 | 8.2 |
| Labor and delivery or inpatient obstetrics/gynecology service | 25,231 | 38.9 |
| Birthing center | 725 | 1.1 |
| Inpatient non-obstetric service | 2,066 | 3.2 |
| Other* | 3,645 | 5.6 |
| Health facility type | ||
| University medical center | 20,195 | 31.2 |
| Regional hospital | 44,608 | 68.8 |
| Pregnancy trimester at presentation (in the health system) | ||
| First trimester (up to 13 weeks gestation) | 19,130 | 29.5 |
| Second trimester (14–27 weeks) | 14,689 | 22.7 |
| Third trimester (28 weeks to delivery) | 30,981 | 47.8 |
| Substance use | ||
| Current substance use | 4,023 | 6.2 |
| Prior substance use | 2,742 | 4.2 |
| HIV/STI screening | ||
| Completed HIV test during pregnancy | 53,401 | 82.4 |
| Tested positive for HIV during pregnancy | 42 | 0.1** |
| Completed Neisseria gonorrhoeae test during pregnancy | 46,455 | 71.7 |
| Tested positive for Neisseria gonorrhoeae during pregnancy | 308 | 0.5 |
| Completed Chlamydia trachomatis test during pregnancy | 46,746 | 72.1 |
| Tested positive for Chlamydia trachomatis during pregnancy | 1,495 | 2.3 |
Abbreviations: HIV, Human Immunodeficiency Virus; STI, sexually transmitted infection.
Includes laboratories, imaging centers, unspecified inpatient and outpatient settings, and other settings that are not included in the above categories, such as physical therapy and nutrition centers.
Rounded from 0.06%.
Syphilis screening cascade
At least one syphilis test was recorded in nearly all (99.5%) pregnancies (Table 3, Figure 1). Syphilis screening was recorded prior to 28 weeks of gestation in 76.5% of pregnancies, between 28–31 weeks of gestation in 27.6%, and within one week of delivery in 96.5%. Syphilis screening was recorded at all required timepoints in 22.0% of pregnancies overall. Among women who presented for care in the health system before the third trimester, syphilis testing was recorded prior to 28 weeks of gestation in 86.1% of pregnancies, between 28–31 weeks of gestation in 40.6%, within one week of delivery in 95.2%, and at all three timepoints in 34.6%. Among women who presented for care before the second trimester, syphilis screening was recorded prior to 28 weeks of gestation in 92.2%, between 28–31 weeks of gestation in 47.3%, within one week of delivery in 95.1% and at all three timepoints in 42.7% of pregnancies.
Table 3.
Engagement in the syphilis screening cascade among pregnant women by pregnancy in a North Carolina health system, 1/1/2019–12/31/2023.
| n/N | % | |
|---|---|---|
| Engagement in the syphilis screening cascade among all women presenting for pregnancy- or delivery-related care | ||
| At least 1 syphilis test completed during pregnancy | 64,460/64,803 | 99.5 |
| Syphilis test completed prior to 28 weeks of gestation | 49,560/64,803 | 76.5 |
| Syphilis test completed between 28–31 weeks of gestation | 17,869/64,803 | 27.6 |
| Syphilis test completed within 1 week of delivery | 62,565/64,803 | 96.5 |
| Syphilis tests completed prior to 28 weeks of gestation, between 28–31 weeks of gestation, and within 1 week of delivery | 14,279/64,803 | 22.0 |
| Engagement in the syphilis screening cascade among women who presented for care before the third trimester | ||
| At least 1 syphilis test completed during pregnancy | 33,658/33,819 | 99.5 |
| Syphilis test completed prior to 28 weeks of gestation | 29,102/33,819 | 86.1 |
| Syphilis test completed between 28–31 weeks of gestation | 13,736/33,819 | 40.6 |
| Syphilis test completed within 1 week of delivery | 32,183/33,819 | 95.2 |
| Syphilis tests completed prior to 28 weeks of gestation, between 28–31 weeks of gestation, and within 1 week of delivery | 11,715/33,819 | 34.6 |
| Engagement in the syphilis screening cascade among women who presented for care before the second trimester | ||
| At least 1 syphilis test completed during pregnancy | 19,093/19,130 | 99.8 |
| Syphilis test completed prior to 28 weeks of gestation | 17,646/19,130 | 92.2 |
| Syphilis test completed between 28–31 weeks of gestation | 9,050/19,130 | 47.3 |
| Syphilis test completed within 1 week of delivery among those who presented before the second trimester | 18,197/19,130 | 95.1 |
| Syphilis tests completed prior to 28 weeks of gestation, between 28–31 weeks of gestation, and within 1 week of delivery | 8,177/19,130 | 42.7 |
Figure 1.
Syphilis Screening Cascade for Pregnant Women by Pregnancy, 1/1/2019 to 12/31/2023.
Compared to women ≥35 years of age, syphilis screening rates at all three timepoints were higher in pregnancies among women aged 18–24 years (PR=1.15; 95% CI, 1.10–1.21), aged 25–29 years (PR=1.08; 95% CI: 1.03–1.13), and aged 30–34 years (PR=1.05; 95% CI: 1.00–1.10) (Table 4). Compared to White women, syphilis screening at all three timepoints was less frequent in pregnancies among Black/African American women (PR=0.93; 95% CI: 0.89–0.96). Completion of all required syphilis screening was less common in pregnancies among women who preferred to use a non-English language for healthcare communication compared to those preferring English (PR=0.85; 95% CI: 0.81–0.90), and more common among those who were self-pay compared to those with private insurance (PR=1.33; 95% CI: 1.27–1.39).
Table 4.
Associations between sociodemographic and clinical factors and completion of required prenatal syphilis screening (by pregnancy) in a North Carolina health system, 1/1/2019–12/31/2023.
| n/N (%) | PR [95% CI]* | P* | |
|---|---|---|---|
| Age (in years) | |||
| <18 | 189/819 (23.1) | 1.12 [0.98–1.27] | 0.097 |
| 18–24 | 3,302/13,884 (23.8) | 1.15 [1.10–1.21] | <0.001 |
| 25–29 | 4,001/17,983 (22.3) | 1.08 [1.03–1.13] | 0.001 |
| 30–34 | 4,316/20,093 (21.5) | 1.05 [1.00–1.10] | 0.030 |
| ≥35 | 2,471/12,024 (20.6) | 1 (Reference) | NA |
| Race | |||
| American Indian/Alaska Native | 200/876 (22.8) | 1.02 [0.90–1.15] | 0.788 |
| Asian | 542/2,415 (22.4) | 1.00 [0.93–1.08] | 0.947 |
| Black/African American | 2,993/14,444 (20.7) | 0.93 [0.89–0.96] | <0.001 |
| Native Hawaiian/Pacific Islander | 27/124 (21.8) | 0.98 [0.70–1.36] | 0.883 |
| White | 7,654/34,279 (22.3) | 1 (Reference) | NA |
| Other | 2,551/11,247 (22.7) | 1.01 [0.97–1.05] | 0.677 |
| Hispanic/Latine ethnicity | 2,688/11,909 (22.6) | 1.03 [0.99–1.06] | 0.198 |
| Non-English language preferred | 1,188/6,214 (19.1) | 0.85 [0.81–0.90] | <0.001 |
| Residence in a rural ZIP code ** | 2,846/12,865 (22.1) | 1.00 [0.96–1.04] | 0.926 |
| Health insurance | |||
| Private | 7,566/35,729 (21.2) | 1 (Reference) | NA |
| Public | 4,855/22,422 (21.7) | 1.02 [0.98–1.05] | 0.307 |
| Self-pay | 1,805/6,377 (28.3) | 1.33 [1.27–1.39] | <0.001 |
| Current substance use | 912/4,023 (22.7) | 1.03 [0.97–1.10] | 0.284 |
| Care setting at initiation of pregnancy episode | |||
| Family medicine, internal medicine, or primary care clinic | 490/1,212 (40.4) | 1.04 [0.97–1.12] | 0.239 |
| Obstetrics/gynecology or women’s health clinic | 10,175/26,152 (38.9) | 1 (Reference) | NA |
| Health department | 186/438 (42.5) | 1.09 [0.97–1.22] | 0.139 |
| Emergency department | 270/5,334 (5.1) | 0.13 [0.12–0.15] | <0.001 |
| Labor and delivery or inpatient obstetrics/gynecology service | 2,218/25,231 (8.8) | 0.23 [0.22–0.24] | <0.001 |
| Birthing center | 93/725 (12.8) | 0.33 [0.27–0.40] | <0.001 |
| Inpatient non-obstetric service | 175/2,066 (8.5) | 0.22 [0.19–0.25] | <0.001 |
| Care setting affiliated with academic medical center (as compared to regional hospital/health center) | 6,365/20,195 (31.5) | 1.76 [1.71–1.81] | <0.001 |
| Pregnancy trimester at presentation | |||
| First trimester (up to 13 weeks gestation) | 8,177/19,130 (42.7) | 1 (Reference) | NA |
| Second trimester (14–27 weeks) | 3,538/14,689 (24.1) | 0.56 [0.55–0.58] | <0.001 |
| Third trimester (28 weeks to delivery) | 2,564/30,981 (8.3) | 0.20 [0.19–0.20] | <0.001 |
| Delivery year | |||
| 2019 | 630/4,548 (13.9) | 1 (Reference) | NA |
| 2020 | 2,682/13,161 (20.4) | 1.46 [1.35–1.58] | <0.001 |
| 2021 | 3,072/14,511 (21.2) | 1.52 [1.41–1.65] | <0.001 |
| 2022 | 3,531/15,866 (22.3) | 1.60 [1.48–1.73] | <0.001 |
| 2023 | 4,364/16,717 (26.1) | 1.87 [1.74–2.02] | <0.001 |
Abbreviations: PR, prevalence ratio; CI, confidence interval; NA, not applicable.
Calculated using log binomial regression with generalized estimating equations (GEE).
Among those who resided in North Carolina.
Compared to pregnancies in which care was initiated at an OB/GYN or women’s health clinic, completion of required syphilis screening was less common among pregnancies in which care was initiated in the emergency department (PR=0.13; 95% CI: 0.12–0.15), at labor and delivery or an inpatient OB/GYN service (PR=0.23; 95% CI: 0.22–0.24), at a birthing center (PR=0.33; 95% CI: 0.27–0.40), or on an inpatient non-obstetric service (PR=0.22; 95% CI: 0.19–0.25). Completion of required syphilis screening in pregnancy was more common among those who received care at the university medical center rather than at a regional hospital/health center (PR=1.76; 95% CI: 1.71–1.81), and less common among those who presented to care at the health system in their second (PR=0.56; 95% CI: 1.71–1.81) or third trimester (PR=0.20, 95% CI=0.19–0.20) as compared to those who presented in the first trimester.
Completion of all required syphilis screening increased over time. Compared to pregnancies among women who delivered in 2019, syphilis screening at all three timepoints was more common in pregnancies among women who delivered in 2020 (PR=1.46; 95% CI: 1.35–1.58), 2021 (PR=1.52; 95% CI: 1.41–1.65), 2022 (PR=1.60; 95% CI: 1.48–1.73), and 2023 (PR=1.87; 95% CI: 1.74–2.02).
Discussion
We found that completion of syphilis testing at all three timepoints during pregnancy--as required by NC law--was low, largely driven by inadequate screening between 28–31 weeks of gestation and the timing of presentation for care in the health system. These findings point to the need for enhanced provider education on the importance of syphilis screening at all required timepoints for identification of maternal syphilis when and where pregnant women present for care, regardless of risk factors.
Syphilis screening in the early third trimester is crucial for detecting new infections or reinfections during pregnancy, and to allow for adequate treatment prior to delivery. To date, only one other study has used EMR data to describe syphilis testing among pregnant women within a health system setting, and specifically investigated completion of one or more syphilis tests (rather than three) to determine the utility of EMR as a tool for evaluating screening in this population.17 Our analyses demonstrate that engagement in the syphilis screening cascade was lower among women who were older, were Black/African American, preferred to use a non-English language for healthcare communication, and those who initially presented for pregnancy- or delivery-related care in emergency departments, birthing centers, or the inpatient setting, suggesting a role for structural interventions to promote syphilis screening for patients in these medically underserved groups and clinical settings.
Our analysis did not include syphilis testing among patients who may have accessed care during their pregnancies at institutions outside of the NC health system. However, our low rate of completion of required syphilis screening among pregnant women in NC is consistent with previously published US data. For example, among commercially insured US women, only 79.6% have been found to complete any syphilis screening during pregnancy.18 Completion of any syphilis screening in pregnancy ranges from 56–91% among Medicaid enrollees in the southern US, with 52.8% receiving syphilis screening during the first trimester, and 72.1% undergoing screening in the third trimester.19
We identified factors associated with inadequate syphilis screening in a state that has required screening during the third trimester and at delivery for over 30 years. These factors may represent patient-level barriers to care, or may be a result of clinician bias or other influences, suggesting areas for further investigation. Previous studies have largely relied on national surveillance databases to describe syphilis screening and prenatal care among mothers of infants with CS or insurance claims data for pregnant women, with limited characterization of maternal factors associated with engagement in syphilis screening during pregnancy.13–15,18,19 Overall, these data underscore the need for interventions to increase prenatal syphilis screening, particularly in the first and third trimesters.
Many of the disparities in prenatal syphilis screening found in our analysis echo disparities in CS diagnoses reported nationally, with disproportionate burden on historically marginalized populations, including Black/African American communities, likely reflecting the complex barriers to care faced by individuals in these groups.20 However, while maternal syphilis rates are higher in younger women,21 we found that older pregnant women were less likely to complete syphilis screening at all three timepoints. Further investigation is needed to determine if this finding reflects decreased suspicion for syphilis in older women among healthcare providers, or if perhaps older women are more likely to refuse syphilis screening when offered in pregnancy.
Low rates of syphilis screening among pregnant women in the US have been attributed to multiple factors, including no or delayed entry into prenatal care, lack of syphilis testing or non-timely syphilis testing, and inadequate provider education.13,14 In 2016, 26.4% of mothers of US CS cases did not receive any prenatal care prior to delivery; furthermore, among those not tested for syphilis at least 30 days before delivery, 80.8% lacked any documented prenatal care at least 30 days before delivery.13 Similarly, in 2022, lack of syphilis testing or non-timely syphilis testing was reported among 36.8% of mothers of US CS cases.14 In our analysis, women who presented for pregnancy-related care earlier in their pregnancies were more likely to complete syphilis screening at all three required timepoints, supporting the findings of these prior studies. Notably, access to prenatal care may be especially challenging for women who live in rural locations.22 This is particularly relevant for NC, which has the second largest rural population among US states.23 Our analysis did not find a difference in rates of syphilis screening at all three timepoints among pregnant women living in rural ZIP codes as compared to those in urban ZIP codes, which may reflect the considerable variation in rurality within ZIP codes in the state. Challenges regarding insurance access have also been highlighted as a major barrier to engagement in prenatal care and prenatal syphilis screening.24 Surprisingly, women who were self-pay were more likely to complete syphilis screening at all three timepoints in our analysis. This could reflect increased concern for syphilis by healthcare providers or more familiarity with prenatal syphilis screening guidelines at clinical sites that serve this population. Further research is needed to determine why syphilis screening is higher among the self-pay population, and how syphilis screening can be improved among those with public and private health insurance. Furthermore, provider adherence to syphilis testing among women experiencing stillbirth has been documented to be less than 10%, despite CDC/ACOG recommendations.25 In NC, there may be inadequate awareness of public health laws among healthcare providers contributing to low rates of completion of required prenatal syphilis screening. Multifaceted interventions are needed to address the drivers of lower prenatal syphilis screening, particularly for women who face challenging—and often overlapping—barriers to care.
Improving access to prenatal care in all settings where pregnant women seek care is essential for promoting required syphilis screening and treatment during pregnancy.14 In our analysis, we found that completion of required syphilis screening was less common among pregnant women who initiated care in emergency departments and inpatient settings. Healthcare encounters outside the traditional prenatal care setting may represent missed opportunities to provide syphilis screening to pregnant women and link them to prenatal care. Opt-out syphilis screening in the acute care setting has been effective at increasing identification of syphilis among pregnant women26 as well as at-risk populations,27,28 and may have utility for increasing syphilis screening among pregnant women who seek care outside of traditional settings. Jails, needle exchange programs, and maternal and child health programs could also be sites of prenatal syphilis screening.14 Rapid and point-of-care tests for prenatal syphilis screening—particularly in the emergency department and other acute care settings—may also increase access to syphilis screening and treatment and reduce delays in care.29 Utilization of the reverse syphilis screening algorithm instead of the traditional algorithm is another testing strategy that may increase identification of maternal syphilis infection.30 Established policies and standardized EMR panels have been documented in settings with high rates of prenatal syphilis screening,31 and have been demonstrated to increase prenatal syphilis screening in the emergency department, which has not traditionally been a site of prenatal care.32 These types of interventions may be particularly helpful for increasing syphilis screening by providers who are not familiar with screening guidelines or who do not typically provide prenatal care.
Educational outreach to providers may also have utility for promoting syphilis screening among pregnant women.31 In our analysis, we found increased rates of syphilis screening completion by year of delivery, which may have been due to public health efforts to raise awareness regarding CS prevention. Similarly, high rates of syphilis screening in care settings at the university medical center may reflect greater awareness of prenatal screening guidelines among providers who may have received more training in the management of pregnant patients. Additionally, educational outreach tailored to women who are reproductive age and/or pregnant may increase syphilis screening by empowering women to request this service from their healthcare providers.33
This analysis had several limitations. As a chart review utilizing data from a single healthcare system, syphilis screening was not captured among women who received prenatal care elsewhere and then delivered their infants within the health system, or among those who moved residences or changed prenatal care providers during their pregnancies. In particular, syphilis screening that occurred early in pregnancy may have been missed among women with high-risk pregnancies necessitating transfer of care to the health system’s maternal-fetal medicine clinics. Furthermore, women who were recorded as presenting in specific settings (i.e. birthing centers) may have been more likely to access prenatal care through providers in the community. However, the rate of syphilis screening among pregnant women in our analysis is consistent with previously published US data, supporting the validity of our findings. Furthermore, when we limited our analysis to patients who had initiated pregnancy-related care by their second trimester, we found that screening rates were still low. Additionally, delays in laboratory processing or clinic scheduling may have occurred because of the COVID-19 pandemic, particularly given the pivot to virtual visits as opposed to in-person visits during the height of the public health emergency. As a result, women who completed syphilis testing outside of the required timepoints were not categorized as having completed syphilis screening. However, this risk was mitigated by capturing syphilis testing completed over a slightly wider time range (between 28–31 weeks of gestation) than at 28–30 weeks. Lastly, we did not have information regarding prior syphilis infection or known HIV infection among the women in our study, and these populations may have higher screening rates.
In summary, we found that nearly all patients received at least one syphilis test during pregnancy, but only a minority received syphilis tests at all three timepoints required by NC law, with the lowest syphilis screening rates between 28–31 weeks of gestation. Our findings demonstrated that receipt of syphilis screening at all required timepoints in pregnancy was lower among women in certain populations, including those who were older, Black/African American, preferred to use a non-English language for healthcare communication, and those who initially presented for pregnancy- or delivery-related care in acute care or inpatient settings. Overall, these findings point to the importance of interventions to support access to prenatal care for all pregnant women, with increased education and reminders for providers to follow screening recommendations. Innovative approaches to improve prenatal syphilis screening, such as implementation of EMR order sets, EMR alerts, and standing orders for routine screening in emergency departments and other non-traditional settings (in communities with a high prevalence of syphilis), may be needed to increase syphilis screening among pregnant women in order to decrease community transmission and CS nationally.
Acknowledgements
We would like to acknowledge the staff at the Carolina Data Warehouse for their assistance with data collection and management. We also wish to express our gratitude to the patients and staff of the University of North Carolina Health System.
Conflicts of Interest and Sources of Funding
The authors report no relevant financial or nonfinancial conflicts of interest. Some of the material in this manuscript has been previously presented as an abstract at the Infectious Disease Week (ID Week) 2025 conference.1 Stephanie Sweitzer is supported by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health under Award Number T32AI007001 and the National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, through Grant Award Number UM1TR004406. The project described was supported by the National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, through Grant Award Number UM1TR004406. This content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Footnotes
Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.
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