Modest improvement in universal prenatal syphilis screening five years after legislation enacted

Abstract

Introduction:

The rate of congenital syphilis increased 498% in Michigan during 2017—2023. Congenital syphilis can be averted if a pregnant woman is screened and treatment initiated ≥30 days before delivery. To strengthen prevention strategies in Michigan, legislation was passed in December 2018 requiring universal prenatal syphilis screening in the first and third trimesters.

Methods:

We analyzed de-identified health claims data from women enrolled in Michigan Medicaid who delivered an infant during 2017—2023. Timing of syphilis screening was estimated by subtracting the date of screening from the date of delivery. Percentage of pregnant women 1) ever screened (280 – 0 days preceding delivery); 2) screened during approximately the first or second trimesters (280 – 94 days preceding delivery) and in the early third trimester (93 – 30 days preceding delivery), jointly and separately; and 3) screened <30 days preceding delivery were calculated and compared pre- (2017) versus 5-years post- (2023) legislation. Absolute percentage changes were evaluated by demographic characteristics, including residence in counties with elevated syphilis among reproductive-aged women (>4.6 cases per 100,000 people); changes <10% were considered stable.

Results:

Over the 7-year study period, 211,289 deliveries were evaluated; approximately half the sample were Non-Hispanic White, half were younger than 27 years (median age), and three-quarters resided in counties with elevated syphilis rates. Screening for syphilis at least once during pregnancy was common (average, 92.0%), as was screening during the first or second trimester (82.3%); screening only <30 days preceding delivery was infrequent (8.9%); percentages were stable pre- and post-legislation (−1.8%, −4.0%, and +1.8%, respectively). Screening in the early third trimester increased post-legislation (37.1% to 53.7%), as did screening in the first or second trimester and repeated in the early third trimester (30.1% to 45.0%). Screening increases were less pronounced in counties with higher syphilis burden compared with lower burden areas. Findings were similar across age and race/ethnicity subgroups.

Conclusion:

Repeat syphilis screenings have increased following legislation requiring universal first and third trimester testing. Strategies to raise awareness of the necessity and value of repeat prenatal syphilis testing, especially in the early third trimester, are important to strengthen congenital syphilis prevention efforts.

Introduction

Congenital syphilis is a devastating and preventable condition resulting from vertical transmission of the bacterium Treponema Pallidum through the placenta and into the fetal bloodstream and can occur at any stage of maternal syphilitic infection, at any point during pregnancy, and can result in miscarriage, severe infant morbidity, stillbirth, or neonatal death [1, 2]. Left untreated, congenital syphilis can result in severe, life-long health consequences such as hepatosplenomegaly, anemia and thrombocytopenia, bone growth abnormalities, seizures, and neurodevelopmental delay [3]. However, nearly all congenital syphilis can be prevented with timely maternal syphilis diagnosis and timely and adequate maternal treatment initiated at least 30 days before delivery; in combination with other clinical and laboratory findings, maternal treatment initiated <30 days preceding delivery is considered a possible congenital syphilis case and requires additional follow-up [2].

The rate of primary and secondary syphilis among women of all ages in Michigan has more than quadrupled from 2017 to 2023 (0.7 to 3.6 per 100,000 population), as has the reported rate of congenital syphilis (9.0 to 53.8 per 100,000 live births) [4,5]. Similar trends have been observed nationally during this period (primary and secondary syphilis among women: 2.3 to 8.1; congenital syphilis: 24.4 to 105.8). Women are considered at geographic syphilis risk by residing in an area with elevated female syphilis rates (>4.6 cases per 100,000) [6]. Among Michigan’s 83 counties, 19 had elevated rates of syphilis in 2023, including Wayne County, home to the City of Detroit. The primary and secondary syphilis rate in the City of Detroit historically exceeds all other health department jurisdictions in the state, including in 2023 [7].

To strengthen congenital syphilis prevention efforts, the State of Michigan passed legislation in December 2018 to require providers to conduct universal opt-out testing of pregnant women for syphilis in the first and third trimesters of pregnancy [8]. For women who were not screened during pregnancy, the law also requires screening at delivery. Michigan Department of Health and Human Services (MDHHS) guidelines have further specified that universal third trimester testing should occur during 28—32 gestational weeks [9] aligned with the same re-screening period as CDC guidelines [10], though CDC’s third trimester syphilis screening recommendation is narrowed to specific subgroups of women considered to be at elevated risk.

Medicaid is a program offering free or reduced cost medical benefits to those who meet certain eligibility criteria, such as pregnancy. Medicaid benefits were expanded in Michigan in April 2014 [11] which has broadened the eligible population for Medicaid services. Of all births that took place in Michigan from 2016 through 2023, Medicaid paid for approximately two of every five (range: 37% to 42%) [12]. The prevention of congenital syphilis is particularly relevant to Medicaid enrollees, as Medicaid is a major payer for the care of sexually transmitted infections [13], and because women whose deliveries were paid for by Medicaid have a greater risk of a syphilis diagnosis at delivery as compared with privately insured or self-pay patients [14]. Assuming providers adhere to the same standard of care delivered to patients regardless of insurance provider, and because eligibility criteria for Michigan Medicaid has not substantively changed since expansion, the pregnant Medicaid population is likely stable over time and can potentially be used as a sentinel population of all births in Michigan to indicate trends in syphilis screening.

To determine whether provider screening patterns in Michigan improved 5 years following a new prenatal screening law, we evaluated the annual percentage of pregnant women screened across different gestational periods (first, second, and third trimesters) among Michigan Medicaid enrollees during 2017 through 2023.

Materials and Methods

De-identified annual billing claims data from Michigan Medicaid enrollees who were women, aged ≥12 years, residents of Michigan, had continuous enrollment in Medicaid benefits in the year preceding the date of delivery, and had delivered an infant during 2017 through 2023 were analyzed. Gestational age at delivery was unavailable and thus the timing during pregnancy in which screenings were conducted was inferred based on date of delivery. Data were accessed via a data sharing agreement with Optum, a vendor and steward of multiple data systems stored in a data warehouse, including Michigan Medicaid data. Pre-existing algorithms produced using Optum’s Symmetry© software identified deliveries and syphilis tests that occurred during pregnancy (within 280 days preceding the date of delivery) based on diagnosis and procedure codes. We then adapted the algorithms to categorize the number of days before delivery that screenings occurred into approximate gestational periods, similar to previously published methods [15]. A total of six screening patterns were built. We assessed women screened at least once during pregnancy (‘ever’ screened 280—0 days preceding delivery). Next, we assessed screening during the approximate first or second trimester and repeat screening in the early third trimester (defined as 280—94 days and repeat screening 93—30 days preceding delivery); these periods were assessed jointly to determine screening in accordance with the legislation and then evaluated separately, regardless of preceding or subsequent screenings, to determine whether either individual period primarily drove trends in the joint metric. We also assessed women screened during approximately the first or second trimester but not during the early third trimester (‘gap’, screened 280—94 days preceding delivery with no repeat screening 93—30 days preceding delivery). Finally, the sixth screening pattern, ‘too late’ (<30 days preceding delivery), was evaluated for women whose syphilis screenings occurred only during the period when initiating treatment would be too late to prevent congenital syphilis.

We calculated annual percentages of pregnant women screened for syphilis by dividing the summed annual total counts of pregnant women screened by the summed annual total counts of pregnant women eligible for screening. Changes in absolute percentage change from 2017 to 2023 were evaluated and those <+/−10% were considered stable. The choice of 10% was arbitrary and was a general attempt to acknowledge minor variation as acceptable for a stable trend. Analyses were conducted overall and stratified by demographic characteristics: age, race/ethnicity, and geographic syphilis risk based on residence in counties with an elevated rate of primary and secondary syphilis (>4.6 cases per 100,000) among women of reproductive age (15—44 years) [6]. All analyses were conducted in STATA 15.0 SE.

Results

We analyzed a total of 211,289 records for Michigan Medicaid enrollees who delivered an infant during the 7-year study period and were eligible for syphilis screening (Table 1); approximately 30,000 were eligible for screening in any given year. The study sample was predominantly young (median age: 27 years old); approximately half were Non-Hispanic White, and one-third were Non-Hispanic Black. Three-quarters of the study sample resided in the subset of 19 Michigan counties with elevated rates of female syphilis; among these, one-third resided in Wayne County.

Table 1.

Characteristics of pregnant women¹ who delivered an infant during 2017—2023 and were eligible for prenatal syphilis screening among Michigan Medicaid enrollees.

Characteristic	Frequency
	N,	(%)
Overall	211,289	(100)
Year of delivery
2017	28,898	(13.7)
2018	29,764	(14.1)
2019	29,460	(13.9)
2020	28,581	(13.5)
2021	31,329	(14.8)
2022	32,334	(15.3)
2023	30,923	(14.6)
Age (years)
12–19	18,599	(8.8)
20–29	125,877	(59.6)
30–39	62,645	(29.6)
≥40	4,168	(2.0)
Race/Ethnicity 2
Black	73,207	(34.6)
White	109,997	(52.1)
Hispanic	14,131	(6.7)
Asian American	3,071	(1.5)
Native Hawaiian/Pacific Islander	192	(0.1)
American Indian/Alaska Native	3,059	(1.4)
Unknown	7,632	(3.6)
Wayne County
Yes	64,992	(30.8)
No	146,297	(69.2)
Geographic Syphilis Risk 3
Yes	153,889	(72.8)
No	57,400	(27.2)

¹We did not limit our analysis to women who delivered singletons and had live births.

²Unless otherwise specified, race/ethnicity is Non-Hispanic.

³Geographic syphilis risk was assigned to counties exceeding the Healthy People 2030 goal to reduce the rate of primary and secondary syphilis among childbearing aged women (15–44 years old) to a rate of 4.6 per 100,000 people during 2023. Michigan counties classified as having geographic syphilis risk include: Alpena, Bay, Branch, Calhoun, Cass, Chippewa, Eaton, Genesee, Ingham, Jackson, Kalamazoo, Kent, Leelanau, Macomb, Monroe, Oakland, Saint Clair, Washtenaw, and Wayne.

Most women delivering an infant during 2017 through 2023 were screened for syphilis at least once (‘ever’) during their pregnancy (92.0% on average each year) and 82.3% were screened during approximately the first or second trimester (Figure 1); these percentages were stable (−1.8%, −4.0%, respectfully) over the study period.

Figure 1.

Percentage of pregnant women screened for syphilis during pregnancy by screening pattern¹ among Michigan Medicaid enrollees, 2017 – 2023.

¹ First or second trimester screening included those who received screening in first or second trimester with or without any preceding or subsequent screening outside of those periods; Early third trimester screening included those who received screening in the early third trimester with or without any preceding or subsequent screening outside of those periods; First or second trimester screening, and repeat screening in the early third trimester, in accordance with new legislation, included those who received screening in the first or second trimester and repeated again in the early third trimester, with or without any preceding or subsequent screening outside of those periods. Screening patterns ‘ever’, ‘gap’ or ‘loo late’ were not included in figures.

Screening during the early third trimester increased by 16.7% (2017: 37.1%; 2023: 53.7%), similar to increases in screening during the first or second trimester coupled with repeat screening during the early third trimester (+14.9%; 2017: 30.1%; 2023: 45.0%).

The percentage of women screened during the first or second trimester but not rescreened during the early third trimester (‘gap’) decreased by 18.9% (2017: 53.8%; 2023: 34.9%). Screening for syphilis that occurred only during the last 29 days of pregnancy, when it would be too late to initiate treatment that would prevent congenital syphilis (‘too late’), was less common (an average of 8.9% each year) and was stable over time (+1.8%; 2017: 7.7%; 2023: 9.5%).

Stratified findings

Trends were similar by racial/ethnic group for women screened at least once during pregnancy, during the first or second trimester, or too late to prevent congenital syphilis (Figure 2), except for Native Hawaiian/Pacific Islanders whose small annual sample sizes may have resulted in less stable percentages over time. Screening during the early third trimester and during the first or second trimester with repeat screening during the early third trimester increased >10% for all except Non-Hispanic Black women, for whom the percentage screened at baseline in 2017 was relatively higher compared with other groups and so, increases in comparison to other groups were slightly smaller over time. Trends in screening patterns did not meaningfully differ across age groups (Figure 3).

Figure 2.

Percentage of pregnant women screened for syphilis during pregnancy by screening pattern¹ and race/ethnicity^2,3 among Michigan Medicaid enrollees, 2017 – 2023.

¹ First or second trimester screening included those who received screening in first or second trimester with or without any preceding or subsequent screening outside of those periods; Early third trimester screening included those who received screening in the early third trimester with or without any preceding or subsequent screening outside of those periods; First or second trimester screening, and repeat screening in the early third trimester, in accordance with new legislation, included those who received screening in the first or second trimester and repeated again in the early third trimester, with or without any preceding or subsequent screening outside of those periods. Screening patterns ‘ever’, ‘gap’ or ‘loo late’ were not included in figures.

² Unless otherwise specified, race/ethnicity is Non-Hispanic.

³ Native Hawaiian/Pacific Islanders whose small annual sample sizes may have resulted in less stable percentages over time.

Figure 3.

Percentage of pregnant women screened for syphilis during pregnancy by screening pattern¹ and age group among Michigan Medicaid enrollees, 2017 – 2023.

¹ First or second trimester screening included those who received screening in first or second trimester with or without any preceding or subsequent screening outside of those periods; Early third trimester screening included those who received screening in the early third trimester with or without any preceding or subsequent screening outside of those periods; First or second trimester screening, and repeat screening in the early third trimester, in accordance with new legislation, included those who received screening in the first or second trimester and repeated again in the early third trimester, with or without any preceding or subsequent screening outside of those periods. Screening patterns ‘ever’, ‘gap’ or ‘loo late’ were not included in figures.

Women ‘ever’ screened for syphilis or screened during the first or second trimester did not meaningfully differ by residence in a county deemed at geographic syphilis risk or by residence in Wayne County (Figure 4). Counties at lower female syphilis risk, and Michigan counties outside of Wayne County, experienced a >20% increase in screening during the early third trimester as well as screening during the first or second trimester with repeat screening in the early third trimester; in contrast, these screening patterns increased <10% in Wayne County. In 2017 and 2018, a higher percentage of women residing in Wayne County were screened during the early third trimester, and screening during the first or second trimester with repeat screening during the early third trimester was higher as compared to women residing elsewhere in the state. However, by 2023, women in Wayne County had lower percentages than those elsewhere in the state for both patterns of screening.

Figure 4.

Percentage of pregnant women screened for syphilis during pregnancy by screening pattern¹ and geography² among Michigan Medicaid enrollees, 2017 – 2023.

¹ First or second trimester screening included those who received screening in first or second trimester with or without any preceding or subsequent screening outside of those periods; Early third trimester screening included those who received screening in the early third trimester with or without any preceding or subsequent screening outside of those periods; First or second trimester screening, and repeat screening in the early third trimester, in accordance with new legislation, included those who received screening in the first or second trimester and repeated again in the early third trimester, with or without any preceding or subsequent screening outside of those periods. Screening patterns ‘ever’, ‘gap’ or ‘loo late’ were not included in figures.

² Geographic syphilis risk was assigned to counties exceeding the Healthy People 2030 goal to reduce the rate of primary and secondary syphilis among childbearing aged women (15–44 years old) to a rate of 4.6 per 100,000 people during 2023. Michigan counties classified at geographic syphilis risk: Alpena, Bay, Branch, Calhoun, Cass, Chippewa, Eaton, Genesee, Ingham, Jackson, Kalamazoo, Kent, Leelanau, Macomb, Monroe, Oakland, Saint Clair, Washtenaw, and Wayne.

Discussion

In this analysis of prenatal screening patterns among Michigan Medicaid enrollees over a 7-year period, we found that five years after enacting legislation that required universal first and third trimester syphilis screening, most women were screened at least once during their pregnancy but fewer than half were screened in accordance with the new law (e.g., screened during the first or second trimester with repeat screening during the early third trimester). Collectively, there were changes in screening patterns that the new law was designed to impact (i.e., increased screening during the early third trimester, increased screening during the first or second trimester and repeat screening during the early third trimester, as well as a decreased screening ‘gap’) and a lack of change in patterns that the new law was not designed to impact (i.e., ‘ever’ screening, screening during the first or second trimester, and only screening ‘too late’ to prevent congenital syphilis); together, these findings suggest that the legislation corresponded to a modest increase in repeat prenatal syphilis screening during the early third trimester.

Michigan’s recent prenatal screening law requires universal opt-out testing in the first and third trimesters as a key strategy to expand screening among women to prevent congenital syphilis. Michigan legislation permits patient refusal of a syphilis test, and while we do not know the extent of refusal in our data, opt-out prenatal STI/HIV testing has historically demonstrated increased levels of prenatal screening as compared to opt-in practices [16, 17] and refusals may be uncommon [18]. Universal screening includes women with lower risk profiles who would typically be excluded under a risk-based testing approach. A universal opt-out testing approach applied to a general population seeking care at a Chicago emergency department reported higher than expected levels of syphilis infection [19], with 33% of identified syphilis cases occurring among women, double the national rate of 14%; while few were pregnant, these findings suggest that expanded screening, especially if focused among women, may identify more maternal syphilis cases and thus present an opportunity to prevent more congenital syphilis. Lack of timely and adequate prenatal care has been identified as a barrier to congenital syphilis prevention efforts [20], suggesting that strategies focused on syphilis testing within the context of prenatal care may need to be coupled with other prevention approaches to maximize congenital syphilis prevention efforts. For example, emergency department use is common among pregnant women [21], including among pregnant Black women residing in the City of Detroit and surrounding suburbs [22]. Elsewhere, emergency department use ≥30 days before delivery was documented for most (57.4%, n=112) women with infants who had congenital syphilis, half of whom reported not receiving prenatal care (n=53) [23]. Expanding universal prenatal syphilis screening to any health encounter, including in emergency departments, may provide broader opportunities to prevent congenital syphilis [20, 24].

As of July 2024, Michigan was one of at least eighteen states with legislation requiring third trimester syphilis testing [25]. To our knowledge, our study is the first to report prenatal screening trends preceding and following the implementation of such a law, and our findings suggest modest uptake of third trimester screening over time in a Medicaid expansion setting. However, in a series of studies across Southern states with varying local policies on third trimester screening and Medicaid expansion, adherence to prenatal syphilis testing was evaluated over time [15, 26]. Generally, states lacking laws for third trimester screening had a smaller proportion tested for syphilis in the third trimester as compared to states with such a law in place [26]. These evaluations used slightly different lengths of time during which screening could occur, which may partially explain the slightly lower levels of ‘ever’, first or second trimester, or early third trimester screening as compared to our findings. Louisiana was the only state included in this previous work that, similar to Michigan, has both a third trimester screening law and Medicaid expansion, but earlier work had combined data across states, so state-specific results could not be directly compared.

Shorter duration of Medicaid enrollment before or during pregnancy corresponded to lower levels of prenatal syphilis screening [15] regardless of risk factors such as STI history [26], a proxy for risk-based testing. Medicaid enrollees with <1 year of enrollment preceding delivery accounted for nearly half [27] or more [15] of the total deliveries analyzed, such that adherence to timely testing outside of the enrollment period is plausible but would not be captured in analyses. In contrast, our study eligibility criteria was narrowed to one-year continuous enrollment preceding delivery, allowing the potential, though not a guarantee, of capturing a greater share of prenatal testing over the course of a given pregnancy. Further, high rates of insurance turnover are common among U.S. women in the periods before and after childbirth [28] and our study limited to those with continuous enrollment, strengthening our ability to draw conclusions about screening patterns over the course of pregnancy. Given Michigan’s status as a Medicaid expansion state [11], women of reproductive age residing in Michigan may have had greater access [29] and adequate use [30] of prenatal care, fewer delays in prenatal care [29], and thus a longer period of opportunity for prenatal testing. Thus, our sample may have included women with more stable access to resources and healthcare, who may have thus been healthier than the general Medicaid population [31], and possibly as compared to analytic samples in previous evaluations.

There was no direct data on whether or to what extent providers in this analysis were made aware of the new legislation, though substantial provider education through contracts with physician training events, academic detailing activities, and an increased number of provider materials [31, 32, 33], was occurring throughout the state to improve testing coverage which may partially explain higher screening levels post-legislation. Better understanding of provider knowledge and attitudes regarding the legislation could inform efforts aimed at ensuring all pregnant women are screened for syphilis during their first and third trimester. Data from laboratory results and diagnosis of congenital syphilis were not available, nor were data on whether treatment was received and whether it was adequate or timely, thus preventing us from concluding whether the new legislation led to an increasing proportion of congenital syphilis cases averted. However, we plan to link Medicaid screening data to surveillance-based reported maternal syphilis cases who were adequately treated for their syphilitic infection to estimate averted congenital syphilis cases over time. Person identifiers were also not available and the enrollees we evaluated may have contributed multiple deliveries during the study period. However, this analysis focused on the required uptake of a universal opt-opt screening approach among providers for each pregnancy analyzed and any changes to the proportion of women who may have missed prenatal visits in subsequent pregnancies likely would not have changed conclusions.

We lacked payer mix data for analyzed providers, so we cannot determine whether those with a larger share of privately insured persons (for whom there may be different cost sharing policies) may have been more reluctant to broadly conduct third trimester testing for all patients in their care [35]. Generalizability to the population of all pregnant women in Michigan was limited as Michigan Medicaid enrollees account for approximately two of every five deliveries in Michigan [12], and our analytic sample was further restricted to enrollees with one year of continuous benefits preceding delivery [36]. Yet, our analyses included information for >200,000 deliveries occurring over a 7-year period and provides some of the first insights into syphilis screening practices pre- and post-legislative change in the context of a Medicaid expansion state.

We lacked gestational age data and thus relied on the number of days preceding delivery to estimate the trimester in which screening occurred; this result may have led to misclassification of screening pattern. Gestational age at delivery is known to vary in a population [37] and can vary by age and race/ethnicity [38]; further, preterm birth occurs among approximately 13% of deliveries with a positive maternal syphilis test [39]. However, using the date of billed services (e.g., delivery and prenatal syphilis testing) is considered valid and reliable in health claims payer data [40, 41], and we anchored all date calculations using the date of delivery. Thus, it is likely that we reliably identified the number of days before delivery that screenings took place; notably, the number of days before delivery is a key factor in defining timely initiation of treatment and thus, effectual prevention of congenital syphilis. In addition, Medicaid claims data may underestimate syphilis screening for Medicaid enrollees [15, 35], so it is possible that adherence to third trimester screening is higher than we observed, though it is unclear whether this error would uniformly impact these data over time.

In the five years following legislation that promoted universal opt-out first and third trimester screening, providers modestly improved testing coverage for syphilis among Michigan Medicaid enrollees. Yet by 2023, half of pregnant women in our study sample were not screened during the early third trimester, suggesting that renewed efforts are needed to promote the importance of repeat screening. Public health agencies could develop strategic partnerships with Medicaid and Managed Care Organizations [42] and leverage these relationships to promote timely repeat testing to their providers and develop quality improvement programs. For example, Michigan Department of Health and Human Services presented screening data to clinical care managers and quality improvement representatives from twelve Michigan Medicaid managed care health plans and discussed strategies to increase provider awareness of repeat third trimester screenings [42]. Plan representatives requested plan-specific data reports, information and tools to facilitate provider communication, and materials for community health workers. MDHHS developed social media messaging to be adapted by health plans as well as training opportunities for continuing education credits. Increasing repeat third trimester screening was included in Michigan Medicaid 2023 strategic plans. Broadly, providers and care organizations across the United States may soon have a healthcare quality evaluation metric which can be used as a tool to track performance on prenatal syphilis screening [43], thus drawing attention to congenital syphilis prevention. Health departments may bolster resources to providers such as a clinical consultation phone line for providers [44] or reducing patient barriers to care with home delivery of syphilis medication [35] or through academic detailing.

Screening during the first or second trimester with repeat screening in the early third trimester increased by fewest percentage points for groups traditionally most at-risk for syphilis, whose 2017 baseline screening were relatively higher than groups traditionally at less risk: Non-Hispanic Black women compared to other racial/ethnic groups, as well as those residing in Michigan counties at higher female syphilis risk as compared to counties at lower female syphilis risk, and those residing in Wayne County compared to counties outside of Wayne County. Our finding of higher levels of baseline screening among traditionally at-risk populations may reflect differences in healthcare access or provider practices.

One in ten women in our study were screened only when it would be too late to initiate treatment to prevent congenital syphilis. Lack of timely testing and treatment is a regularly identified missed opportunity among infants born with congenital syphilis across geographic areas and all racial and ethnic groups [20]. Notably, our evaluation of provider screening adherence does not address the estimated 38% of congenital syphilis cases for whom there was no prenatal care [20] and thus lacking the opportunity for providers to conduct timely screening and treatment. Avoidance or delayed initiation of prenatal care is likely driven by multiple personal and systemic factors, including limited healthcare access [45], prenatal substance use and jurisdiction-specific mandated reporting laws [46], and insurance policy [35]. Full adherence to prenatal syphilis screening at 28 weeks, in addition to full adherence to first trimester screening, would prevent congenital syphilis at low net cost per pregnancy, when considering the current burden of syphilis and medical costs for testing, treatment and congenital syphilis care [27]. Efforts to ensure access to affordable early prenatal care may be critical to an effective and comprehensive congenital syphilis prevention strategy. Community health workers, disease intervention specialists (DIS), and providers in non-traditional venues where reproductive-aged women seek care and services, such as Women, Infants and Children (WIC) programs and other maternal health programs, may promote the benefits of adequate and timely prenatal care for each pregnancy. Promotion of early access to prenatal care can improve various maternal and child health outcomes, including timely testing and treatment to avoid and prevent the severe and potentially fatal effects of congenital syphilis.

Conclusion

Universal, opt-out screenings for syphilis in the first or second trimester and repeated in the early third trimester increased modestly among Michigan Medicaid enrollees following a legislative mandate. Yet, despite rising rates of congenital and maternal syphilis five years following implementation of the prenatal syphilis screening law, approximately half of enrollees were not screened in the early third trimester, underscoring the need for renewed attention to this important congenital syphilis prevention strategy. Future research to estimate the number of congenital syphilis cases averted among women screened will strengthen our understanding of strategies to prevent a devastating but preventable condition.

Key Points:

1. Modest improvements in syphilis screening were observed among Medicaid enrollees after new legislation requiring universal prenatal syphilis screening in the first and third trimesters.

2. While screening modestly increased following passage of legislation, fewer than half of pregnant women were screened during the first and third trimester in accordance with the legislation, underscoring the need for continued focus on timely and repeat syphilis screening.

3. Most pregnant women were screened for syphilis at some point during their pregnancy though one in ten were screened too late to initiate treatment and prevent congenital syphilis (<30 days prior to delivery).