Development of a University-Government Partnership for Public Health Response and Workforce Development in the State of Oregon.

The COVID-19 pandemic exposed and exacerbated a public health workforce shortage and national strategies have called for the development of clear occupational pathways for students to enter the public health workforce and meaningful public health careers. In response to the immediate need for public health workers during the pandemic, several universities and academic hospitals rapidly mobilized students and employees and partnered with local or state health departments. However, many of those partnerships were based on short-term volunteer effort to support critical COVID-19 public health efforts. In this article, we document the development of Oregon's Public Health Practice Team, a student, staff, and faculty workforce developed at the Oregon Health & Science University-Portland State University (OHSU-PSU) School of Public Health in close collaboration with the Oregon Health Authority (OHA). This project contributed significant effort to several phases of Oregon's statewide public health response to COVID-19, and over time developed into a lasting, multi-purpose, inter-agency collaborative public health practice program. Health equity has been centered at every stage of this work. We describe the phases of the partnership development, the current team structure and operations, and highlight key challenges and lessons learned. This provides a case-study of how an innovative and flexible university-government partnership can contribute to immediate pandemic response needs, and also support ongoing public health responses to emerging needs, while contributing to the development of a skilled and diverse public health workforce.

Pregnancy health in a multi-state U.S. population of systemically underserved patients and their children: PROMISE cohort design and baseline characteristics.

BACKGROUND: Gestational weight gain (GWG) is a routinely monitored aspect of pregnancy health, yet critical gaps remain about optimal GWG in pregnant people from socially marginalized groups, or with pre-pregnancy body mass index (BMI) in the lower or upper extremes. The PROMISE study aims to determine overall and trimester-specific GWG associated with the lowest risk of adverse birth outcomes and detrimental infant and child growth in these underrepresented subgroups. This paper presents methods used to construct the PROMISE cohort using electronic health record data from a network of community-based healthcare organizations and characterize the cohort with respect to baseline characteristics, longitudinal data availability, and GWG. METHODS: We developed an algorithm to identify and date pregnancies based on outpatient clinical data for patients 15 years or older. The cohort included pregnancies delivered in 2005-2020 with gestational age between 20 weeks, 0 days and 42 weeks, 6 days; and with known height and adequate weight measures needed to examine GWG patterns. We linked offspring data from birth records and clinical records. We defined study variables with attention to timing relative to pregnancy and clinical data collection processes. Descriptive analyses characterize the sociodemographic, baseline, and longitudinal data characteristics of the cohort, overall and within BMI categories. RESULTS: The cohort includes 77,599 pregnancies: 53% had incomes below the federal poverty level, 82% had public insurance, and the largest race and ethnicity groups were Hispanic (56%), non-Hispanic White (23%) and non-Hispanic Black (12%). Pre-pregnancy BMI groups included 2% underweight, 34% normal weight, 31% overweight, and 19%, 8%, and 5% Class I, II, and III obesity. Longitudinal data enable the calculation of trimester-specific GWG; e.g., a median of 2, 4, and 6 valid weight measures were available in the first, second, and third trimesters, respectively. Weekly rate of GWG was 0.00, 0.46, and 0.51 kg per week in the first, second, and third trimesters; differences in GWG between BMI groups were greatest in the second trimester. CONCLUSIONS: The PROMISE cohort enables characterization of GWG patterns and estimation of effects on child growth in underrepresented subgroups, ultimately improving the representativeness of GWG evidence and corresponding guidelines.

Pelvic floor dysfunction after intervention, compared with expectant management, in prolonged second stage of labour: A population-based questionnaire and cohort study.

OBJECTIVE: To investigate the effect of vacuum extraction (VE) or caesarean section (CS), compared with expectant management, on pelvic floor dysfunction (PFD) 1-2 years postpartum in primiparous women with a prolonged second stage of labour. DESIGN: A population-based questionnaire and cohort study. SETTING: Stockholm, Sweden. POPULATION: A cohort of 1302 primiparous women with a second stage duration of ≥3 h, delivering from December 2017 to November 2018. METHODS: The 1-year follow-up questionnaire from the Swedish National Perineal Laceration Register was distributed 12-24 months postpartum. Exposure was VE or CS at 3-4 h or 4-5 h, compared with expectant management. MAIN OUTCOME MEASURES: Pelvic floor dysfunction was defined as at least weekly symptoms of urinary incontinence, pelvic organ prolapse or a Wexner score of ≥4. The risk of PFD was calculated using Poisson regression with robust variance estimation, presented as crude and adjusted relative risks (RRs and aRRs) with 95% confidence intervals (95% CIs). The implication of obstetric anal sphincter injury (OASI) on pelvic floor disorders was investigated through mediation analysis. RESULTS: In total, 35.1% of women reported PFD. Compared with expectant management, the risk of PFD was increased after VE at 3-4 h (aRR 1.33, 95% CI 1.06-1.65) and 4-5 h (aRR 1.34, 95% CI 1.05-1.70), but remained unchanged after CS. The increased risk after VE was not mediated by OASI. CONCLUSIONS: Pelvic floor dysfunction was common in primiparous women after a prolonged second stage, and the risk of PFD increased after VE but was unaffected by CS, compared with expectant management. If a spontaneous vaginal delivery eventually occurred, allowing an extended duration of labour did not increase the risk of PFD.

Insurance coverage and discontinuity during pregnancy: Frequency and associations documented in the PROMISE cohort.

OBJECTIVE: To describe insurance patterns and discontinuity during pregnancy, which may affect the experiences of the pregnant person: their timely access to care, continuity of care, and health outcomes. DATA SOURCES AND STUDY SETTING: Data are from the PROMISE study, which utilizes data from community-based health care organizations (CHCOs) (e.g., federally qualified health centers that serve patients regardless of insurance status or ability to pay) in the United States from 2005 to 2021. STUDY DESIGN: This descriptive study was a cohort utilizing longitudinal electronic health record data. DATA COLLECTION/EXTRACTION METHODS: Insurance type at each encounter was recorded in the clinical database and coded as Private, Public, and Uninsured. Pregnant people were categorized into one of several insurance patterns. We analyzed the frequency and timing of insurance changes and care utilization within each group. PRINCIPAL FINDINGS: Continuous public insurance was the most common insurance pattern (69.2%), followed by uninsured/public discontinuity (11.8%), with 6.4% experiencing uninsurance throughout the entirety of pregnancy. Insurance discontinuity was experienced by 16.6% of pregnant people; a majority of these reflect people transitioning to public insurance. Those with continuous public insurance had the highest frequency of inadequate prenatal care (19.5%), while those with all three types of insurance during pregnancy had the highest percentage of intensive prenatal care (16.5%). The majority (71.7%-81.2%) of those with a discontinuous pattern experienced a single insurance change. CONCLUSIONS: Insurance discontinuity and uninsurance are common within our population of pregnant people seeking care at CHCOs. Our findings suggest that insurance status should be regarded as a dynamic rather than a static characteristic during pregnancy and should be measured accordingly. Future research is needed to assess the drivers of perinatal insurance discontinuity and if and how these discontinuities may affect health care access, utilization, and birth outcomes.

Hospital Encounters Within 1 Year Postpartum Across Insurance Types, Oregon 2012-2017.

BACKGROUND: Little is known about the timing and frequency of postpartum hospital encounters and postpartum visit attendance and how they may be associated with insurance types. Research on health insurance and its association with postpartum care utilization is often limited to the first 6 weeks. OBJECTIVE: To assess whether postpartum utilization (hospital encounters within 1 year postpartum and postpartum visit attendance within 12 weeks) differs by insurance type at birth (Medicaid, high deductible health plans, and other commercial plans) and whether rates of hospital encounters differ by postpartum visit attendance and insurance status. METHODS: Time-to-event analysis of Oregon hospital births from 2012 to 2017 using All Payer All Claims data. We conducted weighted Cox Proportional Hazard regressions and accounted for differences in insurance type at birth using multinomial propensity scores. RESULTS: Among 202,167 hospital births, 24.9% of births had at least 1 hospital encounter within 1 year postpartum. Births funded by Medicaid had a higher risk of a postpartum emergency department (ED) visit (hazard ratio: 2.05, 95% CI: 1.99, 2.12) and lower postpartum visit attendance (hazard ratio: 0.71, 95% CI: 0.70, 0.72) compared with commercial plans. Among Medicaid beneficiaries, missing the postpartum visit in the first 6 weeks was associated with a lower risk of subsequent readmissions (adjusted hazard ratio 0.77, 95% CI: 0.68, 0.87) and ED visits (adjusted hazard ratio: 0.87 (0.85, 0.88). CONCLUSIONS: Medicaid beneficiaries received more care in the ED within 1 year postpartum compared with those enrolled in other commercial plans. This highlights potential issues in postpartum care access.

Severe Perineal Lacerations in First Delivery: Association with Subsequent Reproductive Outcomes.

Background: Severe perineal lacerations (SPLs), common worldwide, are associated with short- and long-term complications: pelvic floor disorders, fecal incontinence, fistula, and profound psychological impacts. Limited research suggests that experiencing SPL may influence future reproductive intentions, but research on outcomes is lacking. Methods: We analyzed the effect of experiencing SPL during a first delivery among a large cohort of Swedish births between 1992 and 2013. We used linear and multinomial logistic regression to estimate the associations between SPL and four reproductive outcomes: subsequent total birth number, probability of a second birth, interpregnancy interval (IPI), and subsequent scheduled cesarean birth. Results: Among 947,035 singleton live-born first-births, we found that experiencing SPL was associated with slightly fewer overall births in fully adjusted models (a decrease of -0.020 births; 95% confidence interval [CI]: -0.028 to -0.012), but no difference in the probability of a second birth (risk ratio [RR]: 1.00; 95% CI: 0.99 to 1.00) or IPI. Scheduled cesarean was increased in births after SPL (adjusted RR: 4.57; 95% CI: 4.42 to 4.73). A secondary comparison of SPL to severe postpartum hemorrhage suggests that some of these observed differences may be related to experiencing any severe outcome, and some specifically to perineum disruption. Conclusion: This study provides a deeper understanding of the long-term impacts of SPL, which may be useful in informing best clinical practices for supporting women who have experienced SPL.

Pre-Pregnancy Health Risks by Presence and Extent of Disability, 2019-2020.

INTRODUCTION: Prior studies have shown that, compared to non-disabled women, women with disabilities have a higher burden of preconception mental and physical health risks that are associated with adverse pregnancy outcomes. This cross-sectional study assesses how the extent of disability relates to pre-pregnancy health risks. METHODS: This study used 2019-2020 PRAMS data from 22 sites that included the Washington Group Short Set of Questions on Disability (n=37,006). In 2023, associations between extent of disability (none [reference group], some difficulty, or a lot of difficulty) and preconception health risks were examined using multivariable Poisson regression with robust standard errors to calculate adjusted prevalence ratios (aPRs) and 95% CIs while controlling for sociodemographic characteristics. Preconception health risks included smoking, heavy drinking, high blood pressure, diabetes, no multivitamin use, and experiencing physical abuse, depression, or obesity. Individual risks were analyzed, as well as the total number of risks experienced. RESULTS: Of respondents, 33.6% had some difficulty and 6.3% had a lot of difficulty. The likelihood of experiencing preconception health risks increased with extent of disability. Compared to respondents with no difficulty, those with some or a lot of difficulty had a higher prevalence of experiencing 1-2 health risks (aPR=1.13, 95% CI 1.09, 1.18; aPR=1.20; 95% CI 1.53, 2.25) and 3+ health risks (aPR=1.86, 95% CI 1.53, 2.25; aPR=2.42, 95% CI 1.98, 2.97), respectively. CONCLUSIONS: Disabled women, especially those with more difficulty, are vulnerable to preconception health risks that could potentially be mitigated before conception. These findings highlight the need for enhanced efforts to support preconception health of disabled women.

Estimating the effect of timing of earned income tax credit refunds on perinatal outcomes: a quasi-experimental study of California births.

BACKGROUND: The largest poverty alleviation program in the US is the earned income tax credit (EITC), providing $60 billion to over 25 million families annually. While research has shown positive impacts of EITC receipt in pregnancy, there is little evidence on whether the timing of receipt may lead to differences in pregnancy outcomes. We used a quasi-experimental difference-in-differences design, taking advantage of EITC tax disbursement each spring to examine whether trimester of receipt was associated with perinatal outcomes. METHODS: We conducted a difference-in-differences analysis of California linked birth certificate and hospital discharge records. The sample was drawn from the linked CA birth certificate and discharge records from 2007-2012 (N = 2,740,707). To predict eligibility, we created a probabilistic algorithm in the Panel Study of Income Dynamics and applied it to the CA data. Primary outcome measures included preterm birth, small-for-gestational age (SGA), gestational diabetes, and gestational hypertension/preeclampsia. RESULTS: Eligibility for EITC receipt during the third trimester was associated with a lower risk of preterm birth compared with preconception. Eligibility for receipt in the preconception period resulted in improved gestational hypertension and SGA. CONCLUSION: This analysis offers a novel method to impute EITC eligibility using a probabilistic algorithm in a data set with richer sociodemographic information relative to the clinical and administrative data sets from which outcomes are drawn. These results could be used to determine the optimal intervention time point for future income supplementation policies. Future work should examine frequent income supplementation such as the minimum wage or basic income programs.

Neighborhood gentrification, displacement, and severe maternal morbidity in California.

Gentrification, a racialized and profit-driven process in which historically disinvested neighborhoods experience an influx of development that contributes to the improvement of physical amenities, increasing housing costs, and the dispossession and displacement of existing communities, may influence the risk of severe maternal morbidity (SMM). Leveraging a racially diverse population-based sample of all live hospital births in California between 2006 and 2017, we examined associations between neighborhood-level gentrification and SMM. SMM was defined as having one of 21 procedures and diagnoses, as described in the SMM index developed by Centers for Disease Control and Prevention. We compared three gentrification measures to determine which operationalization best captures aspects of gentrification most salient to SMM: Freeman, Landis 3-D, and Urban Displacement Project Gentrification and Displacement Typology. Descriptive analysis assessed bivariate associations between gentrification and birthing people's characteristics. Overall and race and ethnicity-stratified mixed-effects logistic models assessed associations between gentrification and SMM, adjusting for individual sociodemographic and pregnancy factors while accounting for clustering by census tract. The study sample included 5,256,905 births, with 72,718 cases of SMM (1.4%). The percentage of individuals living in a gentrifying neighborhood ranged from 5.7% to 11.7% across exposure assessment methods. Net of individual and pregnancy-related factors, neighborhood-level gentrification, as measured by the Freeman method, was protective against SMM (OR = 0.89, 95% CI: 0.86-0.93); in comparison, gentrification, as measured by the Gentrification and Displacement Typology, was associated with greater risk of SMM (OR = 1.18, 95% CI: 1.14-1.23). These associations were significant among non-Hispanic White, non-Hispanic Black, and Hispanic individuals. Findings demonstrate that gentrification plays a role in shaping the risk of SMM among birthing people in California. Differences in how gentrification is conceptualized and measured, such as an emphasis on housing affordability compared to a broader characterization of gentrification's multiple aspects, may explain the heterogeneity in the directions of observed associations.

Postpartum Hospital Readmissions With and Without Severe Maternal Morbidity Within 1 Year of Birth, Oregon, 2012-2017.

Postpartum readmissions (PPRs) represent a critical marker of maternal morbidity after hospital childbirth. Most severe maternal morbidity (SMM) events result in a hospital admission, but most PPRs do not have evidence of SMM. Little is known about PPR and SMM beyond the first 6 weeks postpartum. We examined the associations of maternal demographic and clinical factors with PPR within 12 months postpartum. We categorized PPR as being with or without evidence of SMM to assess whether risk factors and timing differed. Using the Oregon All Payer All Claims database, we analyzed hospital births from 2012-2017. We used log-binomial regression to estimate associations between maternal factors and PPR. Our final analytical sample included 158,653 births. Overall, 2.6% (n = 4,141) of births involved at least 1 readmission within 12 months postpartum (808 (19.5% of PPRs) with SMM). SMM at delivery was the strongest risk factor for PPR with SMM (risk ratio (RR) = 5.55, 95% confidence interval (CI): 4.14, 7.44). PPR without SMM had numerous risk factors, including any mental health diagnosis (RR = 2.10, 95% CI: 1.91, 2.30), chronic hypertension (RR = 2.17, 95% CI: 1.85, 2.55), and prepregnancy diabetes (RR = 2.85, 95% CI: 2.47, 3.30), all which were on par with SMM at delivery (RR = 1.89, 95% CI: 1.49, 2.40).

Remapping racial and ethnic inequities in severe maternal morbidity: The legacy of redlining in California.

BACKGROUND: Historical mortgage redlining, a racially discriminatory policy designed to uphold structural racism, may have played a role in producing the persistently elevated rate of severe maternal morbidity (SMM) among racialised birthing people. OBJECTIVE: This study examined associations between Home-Owner Loan Corporation (HOLC) redlining grades and SMM in a racially and ethnically diverse birth cohort in California. METHODS: We leveraged a population-based cohort of all live hospital births at ≥20 weeks of gestation between 1997 and 2017 in California. SMM was defined as having one of 21 procedures and diagnoses, per an index developed by Centers for Disease Control and Prevention. We characterised census tract-level redlining using HOLC's security maps for eight California cities. We assessed bivariate associations between HOLC grades and participant characteristics. Race and ethnicity-stratified mixed effects logistic regression models assessed the risk of SMM associated with HOLC grades within non-Hispanic Black, Asian/Pacific Islander, American Indian/Alaskan Native and Hispanic groups, adjusting for sociodemographic information, pregnancy-related factors, co-morbidities and neighbourhood deprivation index. RESULTS: The study sample included 2,020,194 births, with 24,579 cases of SMM (1.2%). Living in a census tract that was graded as "Hazardous," compared to census tracts graded "Best" and "Still Desirable," was associated with 1.15 (95% confidence interval [CI] 1.03, 1.29) and 1.17 (95% CI 1.09, 1.25) times the risk of SMM among Black and Hispanic birthing people, respectively, independent of sociodemographic factors. These associations persisted after adjusting for pregnancy-related factors and neighbourhood deprivation index. CONCLUSIONS: Historical redlining, a tool of structural racism that influenced the trajectory of neighbourhood social and material conditions, is associated with increased risk of experiencing SMM among Black and Hispanic birthing people in California. These findings demonstrate that addressing the enduring impact of macro-level and systemic mechanisms that uphold structural racism is a vital step in achieving racial and ethnic equity in birthing people's health.

Structural racism and adverse maternal health outcomes: A systematic review.

In the United States, racial disparities in adverse maternal health outcomes remain a pressing issue, with Black women experiencing a 3-4 times higher risk of maternal mortality and a 2-3 times higher risk of severe maternal morbidity. Despite recent encouraging efforts, fundamental determinants of these alarming inequities (e.g. structural racism) remain understudied. Approaches that address these structural drivers are needed to then intervene upon root causes of adverse maternal outcomes and their disparities and to ultimately improve maternal health across the U.S. In this paper, we offer a conceptual framework for studies of structural racism and maternal health disparities and systematically synthesize the current empirical epidemiologic literature on the links between structural racism measures and adverse maternal health outcomes. For the systematic review, we searched electronic databases (Pubmed, Web of Science, and EMBASE) to identify peer-reviewed U.S. based quantitative articles published between 1990 and 2021 that assessed the link between measures of structural racism and indicators of maternal morbidity/mortality. Our search yielded 2394 studies and after removing duplicates, 1408 were included in the title and abstract screening, of which 18 were included in the full text screening. Only 6 studies met all the specified inclusion criteria for this review. Results revealed that depending on population sub-group analyzed, measures used, and covariates considered, there was evidence that structural racism may increase the risk of adverse maternal health outcomes. This review also highlighted several areas for methodological and theoretical development in this body of work. Future work should more comprehensively assess structural racism in a way that informs policy and interventions, which can ameliorate its negative consequences on racial/ethnic disparities in maternal morbidity/mortality.

Racial/ethnic disparities in severe maternal morbidity: An intersectional lifecourse approach.

Despite long-existing calls to address alarming racial/ethnic gaps in severe maternal morbidity (SMM), research that considers the impact of intersecting social inequities on SMM risk remains scarce. Invoking intersectionality theory, we sought to assess SMM risk at the nexus of racial/ethnic marginalization, weathering, and neighborhood/individual socioeconomic disadvantage. We used birth hospitalization records from California across 20 years (1997-2017, N = 9,806,406) on all live births ≥20 weeks gestation. We estimated adjusted average predicted probabilities of SMM at the combination of levels of race/ethnicity, age, and neighborhood deprivation or individual socioeconomic status (SES). The highest risk of SMM was observed among Black birthing people aged ≥35 years who either resided in the most deprived neighborhoods or had the lowest SES. Black birthing people conceptualized to be better off due to their social standing (aged 20-34 years and living in the least deprived neighborhoods or college graduates) had comparable and at times worse risk than White birthing people conceptualized to be worse off (aged ≥35 years and living in the most deprived neighborhoods or had a high-school degree or less). Our findings highlight the need to explicitly address structural racism as the driver of racial/ethnic health inequities and the imperative to incorporate intersectional approaches.

Perinatal Health Risks And Outcomes Among US Women With Self-Reported Disability, 2011-19.

Women with disabilities experience elevated risk for adverse pregnancy outcomes. Most studies have inferred disabilities from diagnosis codes, likely undercounting disabilities. We analyzed data, including self-reported disability status, from the National Survey of Family Growth for the period 2011-19. We compared respondents with and without disabilities on these characteristics: smoking during pregnancy, delayed prenatal care, preterm birth, and low birthweight. A total of 19.5 percent of respondents who had given birth reported a disability, which is a much higher prevalence than estimates reported in US studies using diagnosis codes. Respondents with disabilities were twice as likely as those without disabilities to have smoked during pregnancy (19.0 percent versus 8.9 percent). They also had 24 percent and 29 percent higher risk for preterm birth and low birthweight, respectively. Our findings suggest that studies using diagnosis codes may represent only a small proportion of pregnancies among people with disabilities. Measurement and analysis of self-reported disability would facilitate better understanding of the full extent of disability-related disparities, per the Affordable Care Act.

The duration of spontaneous active and pushing phases of labour among 75,243 US women when intervention is minimal: A prospective, observational cohort study.

Background: Friedman's curve, despite acknowledged limitations, has greatly influenced labour management. Interventions to hasten birth are now ubiquitous, challenging the contemporary study of normal labour. Our primary purpose was to characterise normal active labour and pushing durations in a large, contemporary sample experiencing minimal intervention, stratified by parity, age, and body mass index (BMI). Methods: This is a secondary analysis of the national, validated Midwives Alliance of North America 4·0 (MANA Stats) data registry (n = 75,243), prospectively collected between Jan 1, 2012 and Dec 31, 2018 to describe labour and birth in home and birth center settings where common obstetric interventions [i.e., oxytocin, planned cesarean] are not available. The MANA Stats cohort includes pregnant people who intended birth in these settings and prospectively collects labour and birth processes and outcomes regardless of where birth or postpartum care ultimately occurs. Survival curves were calculated to estimate labour duration percentiles (e.g. 10th, 50th, 90th, and others of interest), by parity and sub-stratified by age and BMI. Findings: Compared to multiparous women (n = 32,882), nulliparous women (n = 15,331) had significantly longer active labour [e.g., median 7.5 vs. 3.3 h; 95th percentile 34.8 vs. 12.0 h] and significantly longer pushing phase [e.g., median 1.1 vs. 0.2 h; 95th percentile 5.5 vs. 1.1 h]. Among nulliparous women, maternal age >35 was associated with longer active first stage of labour and longer pushing phase, and BMI >30 kg/m² was associated with a longer active first stage of labour but a shorter pushing phase. Patterns among multiparous women were different, with those >35 years of age experiencing a slightly more rapid active labour and no difference in pushing duration, and those with BMI >30 kg/m² experiencing a slightly longer active labour but, similarly, no difference in pushing duration. Interpretation: Nulliparous women had significantly longer active first stage and pushing phase durations than multiparous women, with further variation noted by age and by BMI. Contemporary US women with low-risk pregnancies who intended birth in settings absent common obstetric interventions and in spontaneous labour with a live, vertex, term, singleton, non-anomalous fetus experienced labour durations that were often longer than prior characterizations, particularly among nulliparous women. Results overcome prior and current sampling limitations to refine understanding of normal labour durations and time thresholds signaling 'labour dystocia'. Funding: OHSU Nursing Innovation and OHSU University Shared Resources.

Accurate identification of cohort study designs in perinatal research: a practical guide.

Study designs are often mischaracterized in the obstetrics literature; in particular, the designation of studies as retrospective (historical) cohorts is frequently in error to describe studies that are prospective cohorts. This is especially true for studies based on electronic health records, which often should be properly considered as prospective cohorts. Epidemiologic study designs were developed in earlier eras of research and healthcare when researchers directly contacted study participants or relied on data from paper medical records. Accordingly, standard epidemiologic study design definitions are difficult to apply to digitized data, which have become common in the modern era of healthcare and computing. In this article, we briefly review the characteristics of the 3 main types of cohort studies. Afterward, we build on existing definitions by proposing several subdesignations of prospective cohort studies that we believe will reduce the confusion in terminology. We provide illustrative examples from obstetrics to concretely demonstrate connections and distinctions among study designs. First, a prospective cohort study can be "active" (participants are deliberately and explicitly enrolled in a prospective research study) or "passive" (participants are followed up in real time for some nonresearch activity, such as clinical care or quality improvement). An active prospective cohort study never stops being a prospective cohort study; however, when reused to answer a new, secondary question, we propose that this should be called a "reused (active) prospective cohort." The de novo cohort study that answered the original question should be considered an "intended (active) prospective cohort." Lastly, when a randomized controlled trial is reused to study some new questions where the randomization variable is not under study, this is also a subtype of a prospective cohort study, a "repurposed randomized controlled trial." The use of more detailed descriptors to describe prospective cohort studies will enable more accurate identification of this study design going forward. It is likely that further refinements will be needed in the future, given the ongoing evolution of how we engage with patients or participants and how data are collected, stored, and linked.

Impact of Medicaid Expansion on Interpregnancy Interval.

OBJECTIVES: Medicaid expansion under the Affordable Care Act (ACA) improved access to reproductive health care for low-income women and birthing people who were previously ineligible for Medicaid. We aimed to evaluate if the expansion affected the risk of having a short interpregnancy interval (IPI), a preventable risk factor for adverse pregnancy outcomes. METHODS: We evaluated parous singleton births to mothers aged 19 or older from U.S. birth certificate data 2009-2018. We estimated the effect of residing in a state that expanded Medicaid access (expansion status determined at 60 days after the prior live birth) on the risk of having a short IPI (<12 months) using difference-in-differences (DID) methods in linear probability models. We stratified the analyses by maternal characteristics and county-level reproductive health care access. RESULTS: Overall risk of short IPI was 14.9% in expansion states and 16.3% in non-expansion states. The expansion was not associated with a significant change in risk of having a short IPI (adjusted mean percentage point change 1.24 [-1.64, 4.12]). Stratified results also did not provide support for an association. CONCLUSIONS: ACA Medicaid expansion did not have an impact on risk of short IPI. Preventing short IPI may require more comprehensive policy interventions in addition to health care access.