BACKGROUND: Severe maternal morbidity (SMM) is broadly defined as an unexpected and potentially life-threatening event associated with labor and delivery. The Centers for Disease Control and Prevention (CDC) produced 21 different indicators based on International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) hospital diagnostic and procedure codes to identify cases of SMM. OBJECTIVES: To examine existing SMM indicators and determine which indicators identified the most in-hospital mortality at delivery hospitalization. METHODS: Data from the 1993-2015 and 2017-2019 Healthcare Cost and Utilization Project's National Inpatient Sample were used to report SMM indicator-specific prevalences, in-hospital mortality rates, and population attributable fractions (PAF) of mortality. We hierarchically ranked indicators by their overall PAF of in-hospital mortality. Predictive modeling determined if SMM prevalence remained comparable after transition to ICD-10-CM coding. RESULTS: The study population consisted of 18,198,934 hospitalizations representing 87,864,173 US delivery hospitalizations. The 15 top ranked indicators identified 80% of in-hospital mortality; the proportion identified by the remaining indicators was negligible (2%). The top 15 indicators were: restoration of cardiac rhythm; cardiac arrest; mechanical ventilation; tracheostomy; amniotic fluid embolism; aneurysm; acute respiratory distress syndrome; acute myocardial infarction; shock; thromboembolism, pulmonary embolism; cerebrovascular disorders; sepsis; both DIC and blood transfusion; acute renal failure; and hysterectomy. The overall prevalence of the top 15 ranked SMM indicators (~22,000 SMM cases per year) was comparable after transition to ICD-10-CM coding. CONCLUSIONS: We determined the 15 indicators that identified the most in-hospital mortality at delivery hospitalization in the US. Continued testing of SMM indicators can improve measurement and surveillance of the most severe maternal complications at the population level.

BACKGROUND: To assist clinicians with identifying children at risk of severe outcomes, we assessed the association between laboratory findings and severe outcomes among severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected children and determined if SARS-CoV-2 test result status modified the associations. METHODS: We conducted a cross-sectional analysis of participants tested for SARS-CoV-2 infection in 41 pediatric emergency departments in 10 countries. Participants were hospitalized, had laboratory testing performed, and completed 14-day follow-up. The primary objective was to assess the associations between laboratory findings and severe outcomes. The secondary objective was to determine if the SARS-CoV-2 test result modified the associations. RESULTS: We included 1817 participants; 522 (28.7%) SARS-CoV-2 test-positive and 1295 (71.3%) test-negative. Seventy-five (14.4%) test-positive and 174 (13.4%) test-negative children experienced severe outcomes. In regression analysis, we found that among SARS-CoV-2-positive children, procalcitonin ≥0.5 ng/mL (adjusted odds ratio [aOR], 9.14; 95% CI, 2.90-28.80), ferritin >500 ng/mL (aOR, 7.95; 95% CI, 1.89-33.44), D-dimer ≥1500 ng/mL (aOR, 4.57; 95% CI, 1.12-18.68), serum glucose ≥120 mg/dL (aOR, 2.01; 95% CI, 1.06-3.81), lymphocyte count <1.0 × 10(9)/L (aOR, 3.21; 95% CI, 1.34-7.69), and platelet count <150 × 10(9)/L (aOR, 2.82; 95% CI, 1.31-6.07) were associated with severe outcomes. Evaluation of the interaction term revealed that a positive SARS-CoV-2 result increased the associations with severe outcomes for elevated procalcitonin, C-reactive protein (CRP), D-dimer, and for reduced lymphocyte and platelet counts. CONCLUSIONS: Specific laboratory parameters are associated with severe outcomes in SARS-CoV-2-infected children, and elevated serum procalcitonin, CRP, and D-dimer and low absolute lymphocyte and platelet counts were more strongly associated with severe outcomes in children testing positive compared with those testing negative.

As SARS-CoV-2 continues to spread and evolve, detecting emerging variants early is critical for public health interventions. Inferring lineage prevalence by clinical testing is infeasible at scale, especially in areas with limited resources, participation, or testing/sequencing capacity, which can also introduce biases. SARS-CoV-2 RNA concentration in wastewater successfully tracks regional infection dynamics and provides less biased abundance estimates than clinical testing. Tracking virus genomic sequences in wastewater would improve community prevalence estimates and detect emerging variants. However, two factors limit wastewater-based genomic surveillance: low-quality sequence data and inability to estimate relative lineage abundance in mixed samples. Here, we resolve these critical issues to perform a high-resolution, 295-day wastewater and clinical sequencing effort, in the controlled environment of a large university campus and the broader context of the surrounding county. We develop and deploy improved virus concentration protocols and deconvolution software that fully resolve multiple virus strains from wastewater. We detect emerging variants of concern up to 14 days earlier in wastewater samples, and identify multiple instances of virus spread not captured by clinical genomic surveillance. Our study provides a scalable solution for wastewater genomic surveillance that allows early detection of SARS-CoV-2 variants and identification of cryptic transmission.

IMPORTANCE: Little is known about the risk factors for, and the risk of, developing post-COVID-19 conditions (PCCs) among children. OBJECTIVES: To estimate the proportion of SARS-CoV-2-positive children with PCCs 90 days after a positive test result, to compare this proportion with SARS-CoV-2-negative children, and to assess factors associated with PCCs. DESIGN, SETTING, AND PARTICIPANTS: This prospective cohort study, conducted in 36 emergency departments (EDs) in 8 countries between March 7, 2020, and January 20, 2021, included 1884 SARS-CoV-2-positive children who completed 90-day follow-up; 1686 of these children were frequency matched by hospitalization status, country, and recruitment date with 1701 SARS-CoV-2-negative controls. EXPOSURE: SARS-CoV-2 detected via nucleic acid testing. MAIN OUTCOMES AND MEASURES: Post-COVID-19 conditions, defined as any persistent, new, or recurrent health problems reported in the 90-day follow-up survey. RESULTS: Of 8642 enrolled children, 2368 (27.4%) were SARS-CoV-2 positive, among whom 2365 (99.9%) had index ED visit disposition data available; among the 1884 children (79.7%) who completed follow-up, the median age was 3 years (IQR, 0-10 years) and 994 (52.8%) were boys. A total of 110 SARS-CoV-2-positive children (5.8%; 95% CI, 4.8%-7.0%) reported PCCs, including 44 of 447 children (9.8%; 95% CI, 7.4%-13.0%) hospitalized during the acute illness and 66 of 1437 children (4.6%; 95% CI, 3.6%-5.8%) not hospitalized during the acute illness (difference, 5.3%; 95% CI, 2.5%-8.5%). Among SARS-CoV-2-positive children, the most common symptom was fatigue or weakness (21 [1.1%]). Characteristics associated with reporting at least 1 PCC at 90 days included being hospitalized 48 hours or more compared with no hospitalization (adjusted odds ratio [aOR], 2.67 [95% CI, 1.63-4.38]); having 4 or more symptoms reported at the index ED visit compared with 1 to 3 symptoms (4-6 symptoms: aOR, 2.35 [95% CI, 1.28-4.31]; ≥7 symptoms: aOR, 4.59 [95% CI, 2.50-8.44]); and being 14 years of age or older compared with younger than 1 year (aOR, 2.67 [95% CI, 1.43-4.99]). SARS-CoV-2-positive children were more likely to report PCCs at 90 days compared with those who tested negative, both among those who were not hospitalized (55 of 1295 [4.2%; 95% CI, 3.2%-5.5%] vs 35 of 1321 [2.7%; 95% CI, 1.9%-3.7%]; difference, 1.6% [95% CI, 0.2%-3.0%]) and those who were hospitalized (40 of 391 [10.2%; 95% CI, 7.4%-13.7%] vs 19 of 380 [5.0%; 95% CI, 3.0%-7.7%]; difference, 5.2% [95% CI, 1.5%-9.1%]). In addition, SARS-CoV-2 positivity was associated with reporting PCCs 90 days after the index ED visit (aOR, 1.63 [95% CI, 1.14-2.35]), specifically systemic health problems (eg, fatigue, weakness, fever; aOR, 2.44 [95% CI, 1.19-5.00]). CONCLUSIONS AND RELEVANCE: In this cohort study, SARS-CoV-2 infection was associated with reporting PCCs at 90 days in children. Guidance and follow-up are particularly necessary for hospitalized children who have numerous acute symptoms and are older.

This cross-sectional study investigates trends in death rates and proportion of deaths by pregnancy period among pregnant and postpartum individuals from 1994 to 2019.

As SARS-CoV-2 continues to spread and evolve, detecting emerging variants early is critical for public health interventions. Inferring lineage prevalence by clinical testing is infeasible at scale, especially in areas with limited resources, participation, or testing/sequencing capacity, which can also introduce biases(1-3). SARS-CoV-2 RNA concentration in wastewater successfully tracks regional infection dynamics and provides less biased abundance estimates than clinical testing(4,5). Tracking virus genomic sequences in wastewater would improve community prevalence estimates and detect emerging variants. However, two factors limit wastewater-based genomic surveillance: low-quality sequence data and inability to estimate relative lineage abundance in mixed samples. Here, we resolve these critical issues to perform a high-resolution, 295-day wastewater and clinical sequencing effort, in the controlled environment of a large university campus and the broader context of the surrounding county. We develop and deploy improved virus concentration protocols and deconvolution software that fully resolve multiple virus strains from wastewater. We detect emerging variants of concern up to 14 days earlier in wastewater samples, and identify multiple instances of virus spread not captured by clinical genomic surveillance. Our study provides a scalable solution for wastewater genomic surveillance that allows early detection of SARS-CoV-2 variants and identification of cryptic transmission.

Hypertensive disorders in pregnancy (HDPs), defined as prepregnancy (chronic) or pregnancy-associated hypertension, are common pregnancy complications in the United States.* HDPs are strongly associated with severe maternal complications, such as heart attack and stroke (1), and are a leading cause of pregnancy-related death in the United States.(†) CDC analyzed nationally representative data from the National Inpatient Sample to calculate the annual prevalence of HDP among delivery hospitalizations and by maternal characteristics, and the percentage of in-hospital deaths with an HDP diagnosis code documented. During 2017-2019, the prevalence of HDP among delivery hospitalizations increased from 13.3% to 15.9%. The prevalence of pregnancy-associated hypertension increased from 10.8% in 2017 to 13.0% in 2019, while the prevalence of chronic hypertension increased from 2.0% to 2.3%. Prevalence of HDP was highest among delivery hospitalizations of non-Hispanic Black or African American (Black) women, non-Hispanic American Indian and Alaska Native (AI/AN) women, and women aged ≥35 years, residing in zip codes in the lowest median household income quartile, or delivering in hospitals in the South or the Midwest Census regions. Among deaths that occurred during delivery hospitalization, 31.6% had any HDP documented. Clinical guidance for reducing complications from HDP focuses on prompt identification and preventing progression to severe maternal complications through timely treatment (1). Recommendations for identifying and monitoring pregnant persons with hypertension include measuring blood pressure throughout pregnancy,(§) including self-monitoring. Severe complications and mortality from HDP are preventable with equitable implementation of strategies to identify and monitor persons with HDP (1) and quality improvement initiatives to improve prompt treatment and increase awareness of urgent maternal warning signs (2).

BACKGROUND: Clinical practices can use telemedicine and other strategies (e.g., self-measured blood pressure [SMBP]) for remote monitoring of hypertension to promote control while decreasing risk of exposure to SARS-CoV-2, the virus that causes COVID-19. METHODS: The DocStyles survey collected data from primary care providers (PCPs), obstetricians-gynecologists (OB/GYNs), and nurse practitioners/physician assistants (NP/PAs) in fall 2020 (n=1,502). We investigated clinical practice changes for monitoring hypertension that were implemented early in the COVID-19 pandemic and examined differences by clinician and practice characteristics (p<0.05). RESULTS: Overall, 369 (24.6%) of clinicians reported their clinical practices made no changes in monitoring hypertension early in the pandemic, 884 (58.9%) advised patients to monitor blood pressure at home or a pharmacy, 699 (46.5%) implemented or increased use of telemedicine for blood pressure monitoring visits, and 545 (36.3%) reduced the frequency of office visits for blood pressure monitoring. Compared with NP/PAs, PCPs were more likely to advise SMBP monitoring (adjusted prevalence ratios (aPR) 1.28, 95% confidence intervals (CI) 1.11-1.47), implement or increase use of telemedicine (aPR 1.23, 95% CI 1.04-1.46) and reduce the frequency of office visits (aPR 1.37, 95% CI 1.11-1.70) for blood pressure monitoring, and less likely to report making no practice changes (aPR 0.63, 95% CI 0.51-0.77). CONCLUSIONS: We noted variation in clinical practice changes by clinician type and practice characteristics. Clinical practices may need additional support and resources to fully maximize telemedicine and other strategies for remote monitoring of hypertension during pandemics and other emergencies that can disrupt routine health care.

OBJECTIVE: Studies from Europe1 reported a reduction in the preterm birth rates early in the COVID-19 pandemic, but data from other world regions offered conflicting evidence.2 In the United States, evidence on preterm birth and stillbirth rates during the pandemic is also mixed.3,4 Existing studies were often limited to specific US hospitals or states or had missing information on stillbirths. We examined the temporal changes in US preterm birth and stillbirth rates by comparing the prepandemic rates with those during a period of reduced population movement (lockdown) and we investigated the geographic variation in the changes by census regions. | | STUDY DESIGN: We used IQVIA's PharMetrics Plus database (IQVIA, Durham, NC) a large convenience sample of claims data that included about one-fifth of US births covered by commercial health insurance, to compare rates between the lockdown period (AprilJune 2020) and a comparison prepandemic period (AprilJune 2019). We identified singleton delivery hospitalizations at 20 weeks gestation using International Classification of Diseases, Tenth Revision, and Current Procedural Terminology codes. We extracted information about the weeks of gestation and birth outcomes (live birth or stillbirth) for each delivery. Preterm birth rates (birth at <37 weeks gestation), late preterm birth rates (birth at 34 to 36 weeks gestation), and early preterm birth rates (birth at <34 weeks gestation) were examined. Stillbirth rates were also examined. We used a logistic regression to compare the birth outcome rates between the 2 time periods, adjusting for census region and maternal age. Although race and ethnicity data were available through data linkages for 12% of the sample, the missing or unknown category in the linked data was still more than 30%, limiting our ability to adjust for or stratify by this variable. We reported the adjusted rate measured in percentage point (%), adjusted rate difference (ARD), and adjusted rate ratio using predictive margins from each regression model. To examine geographic variation, we used interaction terms between the indicator variables for the time period and census region. | | RESULTS: Among 165,433 privately-insured women with singleton deliveries at 20 weeks gestation during the study periods, 0.2% were stillbirths, and 99.8% were live births; and of the live births, approximately 7% were preterm in both the time periods (Table 1). The adjusted rate of preterm birth during the 2020 lockdown was lower than the adjusted rate during the same months in 2019 (7.0% vs 7.4%; ARD=0.4%; 95% CI, 0.6 to 0.1). There was no change in the adjusted rate of stillbirth (ARD=0.02%; 95% CI, 0.07 to 0.02). The reduction in preterm birth was driven by the decrease in late preterm birth (ARD=0.3%; 95% CI, 0.6 to 0.1) (Table 2). The largest reduction in preterm birth was in the Northeast (ARD=1.1; 95% CI, 1.8 to 0.5) (Table 2).

OBJECTIVE: To assess variations in low-risk cesarean delivery rates in the United States using the Society for Maternal-Fetal Medicine (SMFM) definition of low-risk for cesarean delivery and to identify factors associated with low-risk cesarean deliveries. METHODS: From hospital discharge data in the 2018 National Inpatient Sample and State Inpatient Databases, we identified deliveries that were low-risk for cesarean delivery using the SMFM definition based on the International Classification of Diseases, Tenth Revision, Clinical Modification codes. We estimated national low-risk cesarean delivery rates overall and by patient characteristics, clinically relevant conditions not included in the SMFM definition, and hospital characteristics based on the nationally representative sample of hospital discharges in the National Inpatient Sample. Multivariate logistic regressions were estimated for the national sample to identify factors associated with low-risk cesarean delivery. We reported low-risk cesarean delivery rates for 27 states and the District of Columbia based on the annual state data that represented the universe of hospital discharges from participating states in the State Inpatient Databases. RESULTS: Of an estimated 3,634,724 deliveries in the 2018 National Inpatient Sample, 2,484,874 low-risk deliveries met inclusion criteria. The national low-risk cesarean delivery rate in 2018 was 14.6% (95% CI 14.4-14.8%). The rates varied widely by state (range 8.9-18.6%). Nationally, maternal age older than 40 years, non-Hispanic Black or Asian race, private insurance as primary payer, admission on weekday, obesity, diabetes, or hypertension, large metropolitan residence, and hospitals of the South census region were associated with low-risk cesarean delivery. CONCLUSION: Approximately one in seven low-risk deliveries was by cesarean in 2018 in the United States using the SMFM definition and the low-risk cesarean delivery rates varied widely by state.

BACKGROUND: Robust age-specific estimates of anal human papillomavirus (HPV) and high-grade squamous intraepithelial lesions (HSIL) in men can inform anal cancer prevention efforts. We aimed to evaluate the age-specific prevalence of anal HPV, HSIL, and their combination, in men, stratified by HIV status and sexuality. METHODS: We did a systematic review for studies on anal HPV infection in men and a pooled analysis of individual-level data from eligible studies across four groups: HIV-positive men who have sex with men (MSM), HIV-negative MSM, HIV-positive men who have sex with women (MSW), and HIV-negative MSW. Studies were required to inform on type-specific HPV infection (at least HPV16), detected by use of a PCR-based test from anal swabs, HIV status, sexuality (MSM, including those who have sex with men only or also with women, or MSW), and age. Authors of eligible studies with a sample size of 200 participants or more were invited to share deidentified individual-level data on the above four variables. Authors of studies including 40 or more HIV-positive MSW or 40 or more men from Africa (irrespective of HIV status and sexuality) were also invited to share these data. Pooled estimates of anal high-risk HPV (HR-HPV, including HPV16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68), and HSIL or worse (HSIL+), were compared by use of adjusted prevalence ratios (aPRs) from generalised linear models. FINDINGS: The systematic review identified 93 eligible studies, of which 64 contributed data on 29 900 men to the pooled analysis. Among HIV-negative MSW anal HPV16 prevalence was 1·8% (91 of 5190) and HR-HPV prevalence was 6·9% (345 of 5003); among HIV-positive MSW the prevalences were 8·7% (59 of 682) and 26·9% (179 of 666); among HIV-negative MSM they were 13·7% (1455 of 10 617) and 41·2% (3798 of 9215), and among HIV-positive MSM 28·5% (3819 of 13 411) and 74·3% (8765 of 11 803). In HIV-positive MSM, HPV16 prevalence was 5·6% (two of 36) among those age 15-18 years and 28·8% (141 of 490) among those age 23-24 years (p(trend)=0·0091); prevalence was 31·7% (1057 of 3337) among those age 25-34 years and 22·8% (451 of 1979) among those age 55 and older (p(trend)<0·0001). HPV16 prevalence in HIV-negative MSM was 6·7% (15 of 223) among those age 15-18 and 13·9% (166 of 1192) among those age 23-24 years (p(trend)=0·0076); the prevalence plateaued thereafter (p(trend)=0·72). Similar age-specific patterns were observed for HR-HPV. No significant differences for HPV16 or HR-HPV were found by age for either HIV-positive or HIV-negative MSW. HSIL+ detection ranged from 7·5% (12 of 160) to 54·5% (61 of 112) in HIV-positive MSM; after adjustment for heterogeneity, HIV was a significant predictor of HSIL+ (aPR 1·54, 95% CI 1·36-1·73), HPV16-positive HSIL+ (1·66, 1·36-2·03), and HSIL+ in HPV16-positive MSM (1·19, 1·04-1·37). Among HPV16-positive MSM, HSIL+ prevalence increased with age. INTERPRETATION: High anal HPV prevalence among young HIV-positive and HIV-negative MSM highlights the benefits of gender-neutral HPV vaccination before sexual activity over catch-up vaccination. HIV-positive MSM are a priority for anal cancer screening research and initiatives targeting HPV16-positive HSIL+. FUNDING: International Agency for Research on Cancer.

IMPORTANCE: Previous efforts to examine severe maternal morbidity (SMM) in the US have focused on delivery hospitalizations. Little is known about de novo SMM that occurs after delivery discharge. OBJECTIVE: To investigate the incidence, timing, factors, and maternal characteristics associated with de novo SMM after delivery discharge among women in the US. DESIGN, SETTING, AND PARTICIPANTS: In this retrospective cohort study, data from the IBM MarketScan Multi-State Medicaid database and the IBM MarketScan Commercial Claims and Encounters database were used to construct a sample of women aged 15 to 44 years who delivered between January 1, 2010, and September 30, 2014. Severe maternal morbidity was reported by the timing of diagnosis, and the associated maternal characteristics were examined. Women in the Medicaid and commercial insurance sample were classified into 3 distinct outcome groups: (1) those without any SMM during the delivery hospitalization and the postdelivery period (reference group), (2) those who exhibited at least 1 factor associated with SMM during the delivery hospitalization, and (3) those who exhibited any factor associated with de novo SMM after delivery discharge (defined as SMM that was first diagnosed in the inpatient setting during the 6 weeks [or 42 days] after discharge from the delivery hospitalization, conditional on no factor associated with SMM being identified during delivery). Data were analyzed from February to July 2020. EXPOSURES: Timing of SMM diagnosis. MAIN OUTCOMES AND MEASURES: Women with SMM were identified using diagnosis and procedure codes from the International Classification of Diseases, Ninth Revision, Clinical Modification for the 21 factors associated with SMM that were developed by the Centers for Disease Control and Prevention. RESULTS: A total of 2 667 325 women in the US with delivery hospitalizations between 2010 and 2014 were identified; of those, 809 377 women (30.3%) had Medicaid insurance (30.3%; mean [SD] age, 25.6 [5.5] years; 51.1% White), and 1 857 948 women (69.7%; mean [SD] age, 30.6 [5.4] years; 36.4% from the southern region of the US) had commercial insurance. Among those with Medicaid insurance, 17 584 women (2.2%) experienced SMM during the delivery hospitalization, and 3265 women (0.4%) experienced de novo SMM after delivery discharge. Among those with commercial insurance, 32 079 women (1.7%) experienced SMM during the delivery hospitalization, and 5275 women (0.3%) experienced de novo SMM after hospital discharge. A total of 5275 SMM cases (14.1%) and 3265 SMM cases (15.7%) among women with commercial and Medicaid insurance, respectively, developed de novo within 6 weeks after hospital discharge; of those, 3993 cases (75.7%) in the commercial insurance cohort and 2399 cases (73.5%) in the Medicaid cohort were identified in the first 2 weeks after discharge. The most common factors associated with SMM varied based on the timing of diagnosis. In the Medicaid population, non-Hispanic Black women (adjusted odds ratio [aOR], 1.53; 95% CI, 1.48-1.58), Hispanic women (aOR, 1.46; 95% CI, 1.37-1.57), and women of other races or ethnicities (aOR, 1.40; 95% CI, 1.33-1.47) had higher rates of SMM during delivery hospitalization than non-Hispanic White women; however, only the disparity between Black and White women (aOR, 1.69; 95% CI, 1.57-1.81) persisted into the postdischarge period. CONCLUSIONS AND RELEVANCE: In this study, 14.1% of SMM cases in the Medicaid cohort and 15.7% of SMM cases in the commercial insurance cohort first occurred after the delivery hospitalization, with notable disparities in factors and maternal characteristics associated with the development of SMM. These findings suggest a need to expand the focus of SMM assessment to the postdelivery discharge period.

BACKGROUND: Research on prenatal cannabis use and adverse infant outcomes is inconsistent, and findings vary by frequency of use or cigarette use. We assess (1) the prevalence of high frequency (≥once/week), low frequency (<once/week), and any cannabis use during pregnancy by maternal characteristics and adverse infant outcomes; (2) the prevalence of infant outcomes by cannabis use frequency, stratified by cigarette smoking; and (3) the association between cannabis use frequency and infant outcomes, stratified by cigarette smoking. METHODS: Cross-sectional data from 8 states' 2017 Pregnancy Risk Assessment Monitoring System (n = 5548) were analyzed. We calculated adjusted prevalence ratios (aPR) between cannabis use frequency and infant outcomes with Modified Poisson regression. RESULTS: Approximately 1.7 % and 2.6 % of women reported low and high frequency prenatal cannabis use, respectively. Prevalence of use was higher among women with small-for-gestational age (SGA) (10.2 %) and low birthweight (9.7 %) deliveries, and cigarette use during pregnancy (21.2 %). Among cigarette smokers (aPR: 1.8; 95 % CI: 1.1-3.0) and non-smokers (aPR: 2.1; 95 % CI: 1.1-3.9), high frequency cannabis use doubled the risk of low birthweight delivery but did not increase preterm or SGA risk. Regardless of cigarette use, low frequency cannabis use did not significantly increase infant outcome risk. CONCLUSIONS: Prenatal cannabis use was more common among women who smoked cigarettes during pregnancy. High frequency cannabis use was associated with low birthweight delivery, regardless of cigarette use. Healthcare providers can implement recommended substance use screening and provide evidence-based counseling and cessation services to help pregnant women avoid tobacco and cannabis use.

BACKGROUND: Meta-analyses of observational studies have shown that women with a shorter interpregnancy interval (the time from delivery to start of a subsequent pregnancy) are more likely to experience adverse pregnancy outcomes, such as preterm delivery or small for gestational age birth, than women who space their births further apart. However, the studies used to inform these estimates have methodological shortcomings. METHODS: In this commentary, we summarise the discussions of an expert workgroup describing good practices for the design, analysis, and interpretation of observational studies of interpregnancy interval and adverse perinatal health outcomes. RESULTS: We argue that inferences drawn from research in this field will be improved by careful attention to elements such as: (a) refining the research question to clarify whether the goal is to estimate a causal effect vs describe patterns of association; (b) using directed acyclic graphs to represent potential causal networks and guide the analytic plan of studies seeking to estimate causal effects; (c) assessing how miscarriages and pregnancy terminations may have influenced interpregnancy interval classifications; (d) specifying how key factors such as previous pregnancy loss, pregnancy intention, and maternal socio-economic position will be considered; and (e) examining if the association between interpregnancy interval and perinatal outcome differs by factors such as maternal age. CONCLUSION: This commentary outlines the discussions of this recent expert workgroup, and describes several suggested principles for study design and analysis that could mitigate many potential sources of bias.

BACKGROUND: The World Health Organization (WHO) recommends that women wait at least 24 months after a livebirth before attempting a subsequent pregnancy to reduce the risk of adverse maternal, perinatal, and infant health outcomes. However, the applicability of the WHO recommendations for women in the United States is unclear, as breast feeding, nutrition, maternal age at first birth, and total fertility rate differs substantially between the United States and the low- and middle-resource countries upon which most of the evidence is based. METHODS: To inform guideline development for birth spacing specific to women in the United States, the Office of Population Affairs (OPA) convened an expert work group meeting in Washington, DC, on 14-15 September 2017 among reproductive, perinatal, paediatric, social, and public health epidemiologists; obstetrician-gynaecologists; biostatisticians; and experts in evidence synthesis related to women's health. RESULTS: Presentations and discussion topics included the methodological quality of existing studies, evaluation of the evidence for causal effects of short interpregnancy intervals on adverse perinatal and maternal health outcomes, good practices for future research, and identification of research gaps and priorities for future work. CONCLUSIONS: This report provides an overview of the presentations, discussions, and conclusions from the expert work group meeting.

Reductions in births to teens and preterm birth rates are two recent public health successes in the United States (1,2). From 2007 to 2014, the birth rate for females aged 15-19 years declined 42%, from 41.5 to 24.2 per 1,000 females. The preterm birth rate decreased 8.4%, from 10.41% to 9.54% of live births (1). Rates of preterm births vary by maternal age, being higher among the youngest and oldest mothers. It is unknown how changes in the maternal age distribution in the United States have affected preterm birth rates. CDC used birth data to assess the relative contributions of changes in the maternal age distribution and in age-specific preterm birth rates to the overall decrease in preterm birth rates. The preterm birth rate declined in all age groups. The effects of age distribution changes on the preterm birth rate decrease were different in younger and older mothers. The decrease in the proportion of births to mothers aged ≤19 and 20-24 years and reductions in age-specific preterm rates in all age groups contributed to the overall decline in the preterm birth rate. The increase in births to mothers aged ≥30 years had no effect on the overall preterm birth rate decrease. The decline in preterm births from 2007 to 2014 is related, in part, to teen pregnancy prevention and the changing maternal age distribution. Effective public health strategies for further reducing preterm birth rates need to be tailored to different age groups.

BACKGROUND: In response to inconsistent findings, we investigated associations between maternal serum 25-hydroxyvitamin D [25(OH)D] concentrations and infant birthweight for gestational age (BW/GA), including potential effect modification by maternal race/ethnicity and infant sex. METHODS: Data from 2558 pregnant women were combined in a nested case-control study (preterm and term) sampled from three cohorts: the Omega study, the Pregnancy, Infection and Nutrition study, and the Pregnancy Outcomes and Community Health study. Maternal 25(OH)D concentrations were sampled at 4 to 29 weeks gestation (80% 14-26 weeks). BW/GA was modelled as sex and gestational age-specific birthweight z-scores. General linear regression models (adjusting for age, education, parity, pre-pregnancy body mass index, season at blood draw, and smoking) assessed 25(OH)D concentrations in relation to BW/GA. RESULTS: Among non-Hispanic Black women, the positive association between 25(OH)D concentrations and BW/GA was of similar magnitude in pregnancies with female or male infants [beta (beta) = 0.015, standard error (SE) = 0.007, P = 0.025; beta = 0.018, SE = 0.006, P = 0.003, respectively]. Among non-Hispanic White women, 25(OH)D-BW/GA association was observed only with male infants, and the effect size was lower (beta = 0.008, SE = 0.003, P = 0.02). CONCLUSIONS: Maternal serum concentrations of 25(OH)D in early and mid-pregnancy were positively associated with BW/GA among non-Hispanic Black male and female infants and non-Hispanic White male infants. Effect modification by race/ethnicity may be due, in part, to overall lower concentrations of 25(OH)D in non-Hispanic Blacks. Reasons for effect modification by infant sex remain unclear.

BACKGROUND: Vitamin D deficiency during pregnancy has been associated with increased risk of complications and adverse perinatal outcomes. We evaluated seasonal variation of 25-hydroxyvitamin D [25(OH)D] among pregnant women, focusing on patterns and determinants of variation. METHODS: Data came from three cohort studies in the US that included 2583 non-Hispanic Black and White women having prenatal 25(OH)D concentrations determined. Fourier time series and generalised linear models were used to estimate the magnitude of 25(OH)D seasonality. We modelled seasonal variability using a stationary cosinor model to estimate the phase shift, peak-trough difference, and annual mean of 25(OH)D. RESULTS: We observed a peak for 25(OH)D in summer, a nadir in winter, and a phase of 8 months, which resulted from fluctuations in 25(OH)D3 rather than 25(OH)D2. After adjustment for covariates, the annual mean concentrations and estimated peak-trough difference of 25(OH)D among Black women were 19.8 ng/mL [95% confidence interval (CI) 18.9, 20.5] and 5.8 ng/mL [95% CI 4.7, 6.7], and for non-Hispanic White women were 33.0 ng/mL [95% CI 32.6, 33.4] and 7.4 ng/mL [95% CI 6.0, 8.9]. CONCLUSIONS: Non-Hispanic Black women had lower average 25(OH)D concentrations throughout the year and smaller seasonal variation levels than non-Hispanic White women. This study's confirmation of 25(OH)D seasonality over a calendar year has the potential to enhance public health interventions targeted to improve maternal and perinatal outcomes.

PURPOSE: To explore trends in teen birth rates by selected demographics. METHODS: We used birth certificate data and joinpoint regression to examine trends in teen birth rates by age (10-14, 15-17, and 18-19 years) and race during 1981-2006 and by age and Hispanic origin during 1990-2006. Joinpoint analysis describes changing trends over successive segments of time and uses annual percentage change (APC) to express the amount of increase or decrease within each segment. RESULTS: For teens younger than 18 years, the decline in birth rates began in 1994 and ended in 2003 (APC: -8.03% per year for ages 10-14 years; APC: -5.63% per year for ages 15-17 years). The downward trend for 18- and 19-year-old teens began earlier (1991) and ended 1 year later (2004) (APC: -2.37% per year). For each study population, the trend was approximately level during the most recent time segment, except for continuing declines for 18- and 19-year-old white and Asian/Pacific Islander teens. The only increasing trend in the most recent time segment was for 18- and 19-year-old Hispanic teens. During these declines, the age distribution of teens who gave birth shifted to slightly older ages, and the percentage whose current birth was at least their second birth decreased. CONCLUSIONS: Teen birth rates were generally level during 2003/2004-2006 after the long-term declines. Rates increased among older Hispanic teens. These results indicate a need for renewed attention to effective teen pregnancy prevention programs in specific populations.

During the past two decades, there has been an increased use of community-based participatory research in public health activities, especially as part of efforts to understand health disparities affecting communities of color. This article describes the history and lessons learned of a long-standing community participatory project, Healthy African American Families (HAAF), in Los Angeles, California. HAAF evolved from a partnership formed by a community advisory board, university, and federal health agency to an independent, incorporated community organization that facilitates and brokers research and health promotion activities within its community. HAAF created mechanisms for community education and networks of community relationships and reciprocity through which mutual support, research, and interventions are integrated. These sustained, institutionalized relationships unite resources and both community and scientific expertise in a community-partnered participatory research model to address multiple health problems in the community, including preterm birth, HIV, asthma, depression, and diabetes. The HAAF participatory process builds on existing community resiliency and resources and on centuries of self-help, problem-solving, cooperative action, and community activism within the African American community. HAAF demonstrates how community-partnered participatory research can be a mechanism for directing power, collective action, system change, and social justice in the process of addressing health disparities at the community level.

We examined trends in low birth weight (LBW, <2,500 g) rates among US singleton non-Hispanic black infants between 1991 and 2004. We conducted Joinpoint regression analyses, using birth certificate data, to describe trends in LBW, moderately LBW (MLBW, 1,500-2,499 g), and very LBW (VLBW, <1,500 g) rates. We then conducted cross-sectional and binomial regression analyses to relate these trends to changes in maternal or obstetric factors. Non-Hispanic black LBW rates declined -7.35% between 1991 and 2001 and then increased +4.23% through 2004. The LBW trends were not uniform across birth weight subcategories. Among MLBW births, the 1991-2001 decease was -10.20%; the 2001-2004 increase was +5.61%. VLBW did not follow this pattern, increasing +3.84% between 1991 and 1999 and then remaining relatively stable through 2004. In adjusted models, the 1991-2001 MLBW rate decrease was associated with changes in first-trimester prenatal care, cigarette smoking, education levels, maternal foreign-born status, and pregnancy weight gain. The 2001-2004 MLBW rate increase was independent of changes in observed maternal demographic characteristics, prenatal care, and obstetric variables. Between 1991 and 2001, progress occurred in reducing MLBW rates among non-Hispanic black infants. This progress was not maintained between 2001 and 2004 nor did it occur for VLBW infants between 1991 and 2004. Observed population changes in maternal socio-demographic and health-related factors were associated with the 1991-2001 decrease, suggesting multiple risk factors need to be simultaneously addressed to reduce non-Hispanic black LBW rates.