Area-level risk factors for adverse birth outcomes: trends in urban and rural settings

A National Study of the Associations between Hormonal Modulators in Hydraulic Fracturing Fluid Chemicals and Birth Outcomes in the United States of America: A County-Level Analysis

BACKGROUND

Risk of preterm birth (PTB) and low birth weight (LBW) due to hydraulic fracturing (HF) exposure is a growing concern. Regional studies have demonstrated links, but results are often contradictory among studies.

OBJECTIVES

This is the first US national study to our knowledge linking fracturing fluid ingredients to the human hormone pathways targeted-estrogen, testosterone, or other hormones (e.g., thyroid hormone)-to assess the effect of HF ingredients on rates of PTB and LBW.

METHODS

We constructed generalized linear regression models of the impact of HF well density and hormone targeting chemicals in HF fluids (2001-2018) on the county-level average period prevalence rates of PTB and LBW (2015-2018) with each outcome measured in separate models. Our data sources consisted of publicly available datasets, including the WellExplorer database, which uses data from FracFocus, the March of Dimes Peristats, the US Census Bureau, the US Department of Agriculture, and the Centers for Disease Control and Prevention. We conducted additional stratified analyses to address issues of confounding. We used stratification to address issues regarding outcomes in rural vs. urban communities by assessing whether our models achieved similar results in nonmetro counties, as well as farming and mining counties. We also stratified by the year of the HF data to include HF data that was closer to the time of the birth outcomes. We also added covariate adjustment to address other important factors linked to adverse birth outcomes, including the proportion of the population belonging to various racial and ethnic minority populations (each modeled as a separate variable); education (bachelor's degree and high school); use of fertilizers, herbicides, and insecticides, acres of agricultural land per square mile; poverty; insurance status; marital status; population per square mile; maternal care deserts; and drug deaths per 100,000 people.

RESULTS

We found that the density of HF wells in a county was significantly associated with both PTB and LBW rates (percentage of live births) in our fully adjusted models. We report the results from our more restrictive stratified analysis with a subset including only the 2014-2018 data, because this resulted in the most meaningful time frame for comparison. Across all models, the magnitude of effect was highest for wells with ingredients that include estrogen targeting chemicals (ETCs), testosterone targeting chemicals (TTCs) and other hormone targeting chemicals (OHTCs), and, finally, all wells grouped regardless of chemical type. For every unit increase in well density per square mile of wells that use chemicals that include an ETC, we observed a 3.789-higher PTB rate (95% CI: 1.83, 5.74) compared with counties with no ETC wells from 2014 to 2018 and likewise, we observed a 1.964-higher LBW rate (95% CI: 0.41, 3.52). Similarly, for every unit increase in well density per square mile of wells that use TTC, we observed a 3.192-higher PTB rate (95% CI: 1.62, 4.77) compared with counties with no TTC wells. Likewise, for LBW, we found a 1.619-higher LBW rate (95% CI: 0.37, 2.87). We also found that an increase in well density per square mile among wells that use chemicals that include an OHTC resulting in a 2.276-higher PTB rate (95% CI: 1.25, 3.30) compared with counties with no OHTC wells, and for LBW, we found a 1.244-higher LBW rate (95% CI: 0.43, 2.06). We also explored the role of HF well exposure in general (regardless of the chemicals used) and found that an increase in total well density (grouped regardless of hormonal targeting status of the chemicals used) resulted in a 1.228-higher PTB rate (95% CI: 0.66, 1.80) compared with counties with no wells, and for LBW, we found a 0.602-higher LBW rate (95% CI: 0.15, 1.05) compared with counties with no wells. We found similar results in our primary analysis that used all data without any exclusions and the statistical significance did not change.

DISCUSSION

Our findings reinforce previously identified regional associations between HF and PTB and LBW, but on a national scale. Our findings point to dysregulation of hormonal pathways underpinning HF exposure risk on birth outcomes, which warrants further exploration. Future research must consider the specific ingredients used in HF fluids to properly understand the differential effects of exposure. https://doi.org/10.1289/EHP12628.

Navigating Homelessness Assistance While Pregnant: A Rapid Qualitative Research-to-Policy Collaboration in Washington, DC

Background

Homelessness during pregnancy contributes to adverse pregnancy and infant outcomes from birth through early childhood. Washington, DC, a microcosm of structural inequities in the United States, has persistent racial disparities in perinatal outcomes and housing insecurity.

Methods

Grounded in a reproductive justice framework, we explored the lived experience of navigating homelessness assistance while pregnant to inform recommendations for a collaborative policy and practice change effort. We conducted 20 individual interviews with DC residents who experienced homelessness during pregnancy. We analyzed the data using thematic analysis and an action-oriented approach.

Results

Our analysis resulted in three main recommendation areas for policy and practice change: (1) timely and meaningful access to safe and stable housing in pregnancy; (2) care coordination for services and referrals that support physical, mental, and social well-being; and (3) access to a living wage and affordable housing.

Discussion

Access to stable housing is critical to ensure that pregnant and parenting people can have and raise children in a safe and sustainable environment-key tenets of reproductive justice. Housing support must be meaningfully accessible, including service delivery that accommodates the complex social histories and competing demands that accompany housing insecurity.

Health Equity Implications

This study informed the development of strategic recommendations, catalyzed a new model for multisector collaboration, and influenced a system-wide practice change to expand access to robust housing supports for pregnant people. Policy and practice change require sustained leveraging of political will to promote economic justice and ensure that residents can achieve safe, sustainable, and affordable housing.

Effects of land cover and air pollution on the risk of preterm births

OBJECTIVE

To evaluate the association between gestational age and green areas, urban built areas, and the concentration of particulate matter 2.5 (PM2.5) in the city of São Paulo, analyzing the irregular distribution of these areas and pollution levels above the recommended level.

METHODS

The study population consisted of a cohort of live births from 2012, and data from the Live Birth Information System (Sinasc) of the city of São Paulo were used. Using satellite images and supervised classification, the distribution and quantity of green areas and built areas in the city of São Paulo was obtained, as well as the concentrations of PM2.5. Logistic regressions were used to obtain possible associations.

RESULTS

The results of the study show that a lower percentage of green areas is significantly associated with a higher chance of preterm births. A higher building density was positively associated with the odds ratio for preterm birth. We did not find any significant associations between air pollution (PM2.5) and preterm births.

CONCLUSIONS

The results of this study show that greener areas are less associated with preterm births when compared with less green areas.

Disparities in the association between ambient temperature and preterm birth according to individual and regional characteristics: a nationwide time-stratified case-crossover study

BACKGROUND

Several studies have reported that climate change elevates heat exposure in pregnant women and high temperatures during pregnancy are associated with preterm births (PTBs). Although the association might be disproportionate, related evidence remains sparse. We evaluated the disproportionate risk of PTB associated with ambient temperature during pregnancy by individual and regional characteristics in South Korea.

METHODS

We collected data on birth certificates and daily mean temperatures during the period from 2011 to 2019. A time-stratified case-crossover design was used to investigate the association between temperature and PTB and stratified analyses were conducted to examine the effect modification of individual and regional characteristics.

RESULTS

A total of 160,067 singleton PTBs were recorded in Korea from 2011 to 2019. A 5℃ increase in the mean temperature during the last four weeks before delivery was associated with an increased risk of PTB with an odds ratio (OR) of 1.03 (95% confidence interval [CI]: 1.02, 1.05), and the association was more evident in mothers aged ≥35 years (OR: 1.06 [95% CI: 1.03, 1.10]) and with low education levels (OR: 1.04 [95% CI: 1.02, 1.05]). Additionally, the estimated risk was evident in districts with lower medical resources and more prominent disparities were shown by individual and regional characteristics in rural areas than in urban areas.

CONCLUSIONS

This study provides evidence that the risk of PTB related to ambient temperature is disproportionate by individual and regional characteristics and suggests the need for public health policies to alleviate the disparities, especially in rural areas.

Adoption of a National Prophylactic Anticoagulation Guideline for Hospitalized Pregnant Women With COVID-19: Retrospective Cohort Study

BACKGROUND

Both COVID-19 and pregnancy are associated with hypercoagulability. Due to the increased risk for thrombosis, the United States National Institute of Health's recommendation for prophylactic anticoagulant use for pregnant patients has expanded from patients hospitalized for severe COVID-19 manifestation to all patients hospitalized for the manifestation of COVID-19 (no guideline: before December 26, 2020; first update: December 27, 2022; second update: February 24, 2022-present). However, no study has evaluated this recommendation.

OBJECTIVE

The objective of this study was to characterize prophylactic anticoagulant use among hospitalized pregnant people with COVID-19 from March 20, 2020, to October 19, 2022.

METHODS

This was a retrospective cohort study in large US health care systems across 7 states. The cohort of interest was pregnant patients who were hospitalized with COVID-19, without previous coagulopathy or contraindication to anticoagulants (n=2767). The treatment group consisted of patients prescribed prophylactic dose anticoagulation between 2 days before and 14 days after COVID-19 treatment onset (n=191). The control group was patients with no anticoagulant exposure between 14 days before and 60 days after COVID-19 treatment onset (n=2534). We ascertained the use of prophylactic anticoagulants with attention to the updates in guidelines and emerging SARS-CoV-2 variants. We propensity score matched the treatment and control group 1:1 on the most important features contributing to the prophylactic anticoagulant administration status classification. Outcome measures included coagulopathy, bleeding, COVID-19-related complications, and maternal-fetal health outcomes. Additionally, the inpatient anticoagulant administration rate was validated in a nationwide population from Truveta, a collective of 700 hospitals across the United States.

RESULTS

The overall administration rate of prophylactic anticoagulants was 7% (191/2725). It was lowest after the second guideline update (no guideline: 27/262, 10%; first update: 145/1663, 8.72%; second update: 19/811, 2.3%; P<.001) and during the omicron-dominant period (Wild type: 45/549, 8.2%; Alpha: 18/129, 14%; Delta: 81/507, 16%; and Omicron: 47/1551, 3%; P<.001). Models developed on retrospective data showed that the variable most associated with the administration of inpatient prophylactic anticoagulant was comorbidities prior to SARS-CoV-2 infection. The patients who were administered prophylactic anticoagulant were also more likely to receive supplementary oxygen (57/191, 30% vs 9/188, 5%; P<.001). There was no statistical difference in a new diagnosis of coagulopathy, bleeding, or maternal-fetal health outcomes between those who received treatment and the matched control group.

CONCLUSIONS

Most hospitalized pregnant patients with COVID-19 did not receive prophylactic anticoagulants across health care systems as recommended by guidelines. Guideline-recommended treatment was administered more frequently to patients with greater COVID-19 illness severity. Given the low rate of administration and differences between treated and untreated cohorts, efficacy could not be assessed.

Analysis of an Association between Preterm Birth and Parental Educational Level in Japan Using National Data

Preterm birth rate depending on parental educational level in recent years has not been surveyed in Japan. In this study, we showed the trend in preterm birth rate depending on parental educational level from 2000 to 2020 by linking data from the Census regarding individuals' educational level and parents in birth data of the vital statistics. Four types of parental educational level, namely junior high school, high school, technical school or junior college, and university or graduate school, were compared. Slope and relative indexes of inequality for preterm birth by educational level were computed by binomial models. Data on 3,148,711 births and 381,129,294 people were used in the analysis, and data on 782,536 singleton births were used after data linkage. The preterm birth rate (%) for junior high school graduate mothers and fathers was 5.09 and 5.20 in 2020, respectively. Contrarily, the preterm birth rate (%) for parents who graduated from a university or graduate school was 4.24 for mothers and 4.39 for fathers, and the rate tended to increase as educational level decreased, irrespective of parental gender. Results of inequality indexes showed that a statistically significant inequality by parental educational level persisted from 2000 to 2020.

Insights into Prevention of Health Complications in Small for Gestational Age (SGA) Births in Relation to Maternal Characteristics: A Narrative Review

Small for gestational age (SGA) births are a significant clinical and public health issue. The objective of this review was to summarize maternal biological and socio-demographic factors and preventive strategies used to reduce the risk of SGA births. A literature search encompassing data from the last 15 years was conducted using electronic databases MEDLINE/PubMed, Google Scholar and Scopus to review risk factors and preventive strategies for SGA. Current evidence shows that primiparity, previous stillbirths, maternal age ≤24 and ≥35 years, single motherhood, low socio-economic status, smoking and cannabis use during pregnancy confer a significant risk of SGA births. Studies on alcohol consumption during pregnancy and SGA birth weight are inconclusive. Beneficial and preventive factors include the "Mediterranean diet" and dietary intake of vegetables. Periconceptional folic acid supplementation, maternal 25-hydroxyvitamin D, zinc and iron levels are partly associated with birth weight. No significant associations between COVID-19 vaccinations and birthweight are reported. A midwifery-led model based on early and extensive prenatal care reduces the risk of SGA births in women with low socio-economic status. Major preventive measures relate to the awareness of modifiable and non-modifiable risk factors of SGA, leading to changes in parents' lifestyles. These data support that education, monitoring during pregnancy, and implementing preventive strategies are as important as biological determinants in risk reduction of SGA births.

Pregnancy Apps for Self-Monitoring: Scoping Review of the Most Popular Global Apps Available in Australia

Digital health tools, such as apps, have the potential to promote healthy behaviours, especially self-monitoring, which can facilitate pregnancy management and reduce the risk of associated pregnancy health conditions. While pregnancy apps are popular amongst pregnant women, there is limited information about the overall quality of their content or self-monitoring tools and the number of behaviour change techniques (BCTs) that they include. The aim of this study was thus to assess the quality of pregnancy apps for self-monitoring, and their usage of BCTs. We identified pregnancy apps by web scraping the most popular global apps for self-monitoring in the Apple App Store and Google Play Store available in Australia. The app quality was evaluated using the scorecard approach and the inclusion of BCTs was evaluated using the ABACUS tool. We identified 31 pregnancy apps that met our eligibility criteria. We found that pregnancy apps tended to score the highest in the domains of 'cost and time', 'usability', and 'technical', and lowest on 'clinical' and 'end-user requirements'. Additionally, the majority of apps contained minimal BCTs. Based on our findings, we propose a digital health scorecard visualisation that would break down app quality criteria and present them in a more accessible way to clinicians and pregnant users. We conclude that these findings highlight the shortcomings of available commercial pregnancy apps and the utility of a digital health scorecard visualisation that would empower users to make more informed decisions about which apps are the most appropriate for their needs.

Associations between combined exposure to environmental hazards and social stressors at the neighborhood level and individual perinatal outcomes in the ECHO-wide cohort

Limited studies examine how prenatal environmental and social exposures jointly impact perinatal health. Here we investigated relationships between a neighborhood-level combined exposure (CE) index assessed during pregnancy and perinatal outcomes, including birthweight, gestational age, and preterm birth. Across all participants, higher CE index scores were associated with small decreases in birthweight and gestational age. We also observed effect modification by race; infants born to Black pregnant people had a greater risk of preterm birth for higher CE values compared to White infants. Overall, our results suggest that neighborhood social and environmental exposures have a small but measurable joint effect on neonatal indicators of health.

Determinants of adverse birth outcomes among women delivered in public hospitals of Ethiopia, 2020

Background

Adverse birth outcome is a common health problem consisting of several health effects involving pregnancy and the newborn infant. Infants with one or more adverse birth outcomes are at greater risk for mortality and a variety of health and developmental problems. Factors such as the age of the mother, antepartum hemorrhage, history of abortion, gestational age, anemia, and maternal undernutrition have predisposed the mother to adverse birth outcome. For appropriate prevention of the adverse birth outcomes, data pertaining to determinants of adverse birth outcomes are important. Therefore, this study was aimed to assess the determinants of adverse birth outcomes among women who give birth in public hospitals of western Ethiopia.

Methods

An institutional-based unmatched prospective case-control study was conducted from February 15 to April 15, 2020, in selected public hospitals of western Ethiopia. From mothers who gave birth in public hospitals of Wollega zones, 165 cases and 330 controls were selected. Mothers with adverse birth outcomes were cases and mothers without adverse birth were controls. Data was collected by structured interviewer-administered questionnaires. In addition to the interview, the data collectors abstracted clinical data by reviewing the mother and the babies’ medical records. The collected data were entered into Epi info version 7 and exported to SPSS version 21 for analysis. Finally, multivariable logistic regression was used to identify determinants of adverse birth outcomes at P-value < 0.05.

Results

A total of 495 mothers (165 cases and 330 controls) were included in the study with a mean age of 28.48 + 5.908. Low ANC visit (AOR = 3.92: 95% CI; 1.86, 8.2), premature rupture of membrane (AOR = 2.83: 95% CI; 1.72,4.64), being Anemic (AOR = 2: 95% CI; 1.16,3.44), pregnancy induced-hypertension (AOR = 2.3:95% CI; 1.4,3.85), not getting dietary supplementation (AOR = 2.47:95% CI; 1.6,3.82), and physical abuse (AOR = 2.13: 95% CI; 1.05,4.32) were significantly associated with the development of the adverse birth outcome.

Conclusion

Low antenatal care visit, being anemic, premature rupture of membrane, pregnancy-induced hypertension, not getting dietary supplementation, and physical abuse were determinants of adverse birth outcomes. The clinicians should play a pivotal role to improve antenatal care follow up, counsel, and supplement recommended diets and minimize violence and abuse during pregnancy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13690-021-00776-0.

The adverse birth outcome is a common health problem consisting of several health effects involving pregnancy and the newborn infant. Birth outcomes are measures of health at birth and their magnitude is dramatically decreased in the past 40 years. However; there is still a large gap between developing and developed countries. Infants with one or more adverse birth outcomes are at greater risk for mortality and a variety of health and developmental problems. For appropriate prevention of adverse birth outcomes, data pertaining to determinants of adverse birth outcomes are important. An institutional-based unmatched prospective case-control study was conducted from February 15 to April 15, 2020, in selected public hospitals of western Ethiopia. In this study, low Antenatal care (ANC) visits, being anemic, premature rupture of membrane, pregnancy-induced hypertension, not getting dietary supplementation, and physical abuse were determinants of adverse birth outcomes. The clinicians should play a pivotal role to improve ANC follow up, counsel, and supplement recommended diets and minimize violence and abuse during pregnancy.

Association Between Income and Perinatal Mortality in the Netherlands Across Gestational Age

Importance

The association between household income and perinatal health outcomes has been understudied. Examining disparities in perinatal mortality within strata of gestational age and before and after adjusting for birth weight centile can reveal how the income gradient is associated with gestational age, birth weight, and perinatal mortality.

Objectives

To investigate the association between household income and perinatal mortality, separately by gestational age strata and time of death, and the potential role of birth weight centile in mediating this association.

Design, Setting, and Participants

This cross-sectional study used individually linked data of all registered births in the Netherlands with household-level income tax records. Singletons born between January 1, 2004, and December 31, 2016, at 24 weeks to 41 weeks 6 days of gestation with complete information on birth outcomes and maternal characteristics were studied. Data analysis was performed from March 1, 2018, to August 30, 2021.

Exposures

Household income rank (adjusted for household size).

Main Outcomes and Measures

Perinatal mortality, stillbirth (at ≥24 weeks of gestation), and early neonatal mortality (at ≤7 days after birth). Disparities were expressed as bottom-to-top ratios of projected mortality among newborns with the poorest 1% of households vs those with the richest 1% of households. Generalized additive models stratified by gestational age categories, adjusted for potential confounding by maternal age at birth, maternal ethnicity, parity, sex, and year of birth, were used. Birth weight centile was included as a potential mediator.

Results

Among 2 036 431 singletons in this study (1 043 999 [51.3%] males; 1 496 579 [73.5%] with mother of Dutch ethnicity), 121 010 (5.9%) were born before 37 weeks of gestation, and 8720 (4.3 deaths per 1000) died during the perinatal period. Higher household income was positively associated with higher rates of perinatal survival, with an unadjusted bottom-to-top ratio of 2.18 (95% CI, 1.87-2.56). The bottom-to-top ratio decreased to 1.30 (95% CI, 1.22-1.39) after adjustment for potential confounding factors and inclusion of birth weight centile as a possible mediator. The fully adjusted ratios were lower for stillbirths (1.27; 95% CI, 1.20-1.36) than for early neonatal deaths (1.35; 95% CI, 1.14-1.66). Inequalities in perinatal mortality were found for newborns at greater than 26 weeks of gestation but not between 24 and 26 weeks of gestation (fully adjusted bottom-to-top ratio, 0.89; 95% CI, 0.77-1.04).

Conclusions and Relevance

The results of this large nationally representative cross-sectional study suggest that a large part of the increased risk of perinatal mortality among low-income women is mediated via a lower birth weight centile. The absence of disparities at very low gestational ages suggests that income-related risk factors for perinatal mortality are less prominent at very low gestational ages. Further research should aim to understand which factors associated with preterm birth and lower birth weight can reduce inequalities in perinatal mortality.

Racial and ethnic disparities in birth Outcomes: A decomposition analysis of contributing factors

This study seeks to quantify and rank the contribution of selected factors to the observed racial/ethnic disparities in low-birth-weight births (LBWBs) and preterm births (PTBs). Based on vital statistics data on births to primiparous women and characteristics of mothers in the State of Nebraska during the period of 2005 to 2014 (n = 93,375), unadjusted and adjusted odds ratios were estimated to examine the association between selected variables and the odds of having LBWBs or PTBs. Fairlie decomposition analysis was performed to quantify the contribution of each selected factor to racial/ethnic differences in LBWB and PTB rates. The prevalence of PTBs was 9.1% among non-Hispanic White (NHW) women, as compared to 12.8% among non-Hispanic Black (NHB) women and 10.6% among Hispanic women. The corresponding prevalence of LBWBs in the three groups were 5.9%, 11.9%, and 7.2%, respectively. The higher educational attainment among NHW women, relative to NHB women accounted for 10% of the observed difference in LBWB rate between the two groups. Health insurance coverage was the second most important factor accounting for the observed disparities in birth outcomes. Addressing socioeconomic disadvantages in NHB and Hispanic women would be important for them to narrow their gaps with NHW women in LBWB and PTB prevalence. More research is needed to identify key factors leading to the disparities in birth outcomes between NHW and NHB women.

Gene Variants Determine Placental Transfer of Perfluoroalkyl Substances (PFAS), Mercury (Hg) and Lead (Pb), and Birth Outcome: Findings From the UmMuKi Bratislava-Vienna Study

Prenatal exposure to perfluoroalkyl substances (PFAS), bisphenol A (BPA), lead (Pb), total mercury (THg), and methylmercury (MeHg) can affect fetal development. Factors influencing placental transfer rate of these toxins are poorly investigated. Whether prenatal exposure to pollutants has an effect on birth weight is incompletely understood. We therefore aimed (1) to determine placental transfer rates of PFAS, BPA, Pb, THg, and MeHg, (2) to analyze relationships between fetal exposure and birth outcome and (3) to analyze gene variants as mediators of placental transfer rates and birth outcome. Two hundred healthy pregnant women and their newborns participated in the study. BPA, 16 PFAS, THg, MeHg, and Pb were determined using HPLCMS/MS (BPA, PFAS), HPLC-CV-ICPMS (MeHg), CV-AFS (THg), and GF-AAS (Pb). Questionnaires and medical records were used to survey exposure sources and birth outcome. 20 single nucleotide polymorphisms and two deletion polymorphisms were determined by real-time PCR from both maternal and newborn blood. Genotype-phenotype associations were analyzed by categorical regression and logistic regression analysis. Specific gene variants were associated with altered placental transfer of PFAS (ALAD Lys59Asn, ABCG2 Gln141Lys), THg (UGT Tyr85Asp, GSTT1del, ABCC1 rs246221) and Pb (GSTP1 Ala114Val). A certain combination of three gene polymorphisms (ABCC1 rs246221, GCLM rs41303970, HFE His63Asp) was over-represented in newborns small for gestational age. 36% of Austrian and 75% of Slovakian mothers had levels exceeding the HBM guidance value I (2 μg/L) of the German HBM Commission for PFOA. 13% of newborns and 39% of women had Ery-Pb levels above 24 μg/kg, an approximation for the BMDL₀₁ of 12 μg/L set by the European Food Safety Authority (EFSA). Our findings point to the need to minimize perinatal exposures to protect fetal health, especially those genetically predisposed to increased transplacental exposure.

Maternal Ambient Exposure to Atmospheric Pollutants during Pregnancy and Offspring Term Birth Weight in the Nationwide ELFE Cohort

Background: Studies have reported associations between maternal exposure to atmospheric pollution and lower birth weight. However, the evidence is not consistent and uncertainties remain. We used advanced statistical approaches to robustly estimate the association of atmospheric pollutant exposure during specific pregnancy time windows with term birth weight (TBW) in a nationwide study. Methods: Among 13,334 women from the French Longitudinal Study of Children (ELFE) cohort, exposures to PM_2.5, PM₁₀ (particles < 2.5 µm and <10 µm) and NO₂ (nitrogen dioxide) were estimated using a fine spatio-temporal exposure model. We used inverse probability scores and doubly robust methods in generalized additive models accounting for spatial autocorrelation to study the association of such exposures with TBW. Results: First trimester exposures were associated with an increased TBW. Second trimester exposures were associated with a decreased TBW by 17.1 g (95% CI, −26.8, −7.3) and by 18.0 g (−26.6, −9.4) for each 5 µg/m³ increase in PM_2.5 and PM₁₀, respectively, and by 15.9 g (−27.6, −4.2) for each 10 µg/m³ increase in NO₂. Third trimester exposures (truncated at 37 gestational weeks) were associated with a decreased TBW by 48.1 g (−58.1, −38.0) for PM_2.5, 38.1 g (−46.7, −29.6) for PM₁₀ and 14.7 g (−25.3, −4.0) for NO₂. Effects of pollutants on TBW were larger in rural areas. Conclusions: Our results support an adverse effect of air pollutant exposure on TBW. We highlighted a larger effect of air pollutants on TBW among women living in rural areas compared to women living in urban areas.

Urban social environment and low birth weight in 360 Latin American cities

OBJECTIVE

Using data compiled by the SALURBAL project (Urban Health in Latin America; 'Salud Urbana en América Latina') we quantified variability in low birth weight (LBW) across cities in Latin America, and evaluated the associations of socio-economic characteristics at various levels (maternal, sub-city and city) with the prevalence of LBW.

METHODS

The sample included 8 countries, 360 cities, 1321 administrative areas within cities (sub-city units) and birth registers of more than 4.5 million births for the year 2014. We linked maternal education from birth registers to data on socioeconomic characteristics of sub-cities and cities using the closest available national population census in each country. We applied linear and Poisson random-intercept multilevel models for aggregated data.

RESULTS

The median prevalence of city LBW by country ranged from a high of 13% in Guatemala to a low of 5% in Peru (median across all cities was 7.8%). Most of the LBW variability across sub-cities was between countries, but there were also significant proportions between cities within a country, and within cities. Low maternal education was associated with higher prevalence of LBW (Prevalence rate ratios (PRR) for less than primary vs. completed secondary or more 1.12 95% CI 1.10, 1.13) in the fully adjusted model. In contrast, higher sub-city education and a better city social environment index were independently associated with higher LBW prevalence after adjustment for maternal education and age, city population size and city gross domestic product (PRR 1.04 95% CI 1.03, 1.04 per SD higher sub-city education and PRR 1.02 95% CI 1.00, 1.04 per SD higher SEI). Larger city size was associated with a higher prevalence of LBW (PRR 1.06; 95% CI 1.01, 1.12).

CONCLUSION

Our findings highlight the presence of heterogeneity in the distribution of LBW and the importance of maternal education, local and broader social environments in shaping LBW in urban settings of Latin America. Implementing context-sensitive interventions guided to improve women's education is recommended to tackle LBW in the region.

Going the distance: Associations between adverse birth outcomes and obstetric provider distances for adolescent pregnancies in South Carolina

PURPOSE

Distances to obstetric care providers are a persistent concern, especially for rural pregnant adolescents. Births to adolescents are disproportionately affected by adverse birth outcomes (ABOs), yet little is known regarding how driving distances may impact ABOs. This study examines the association between driving distances to obstetric providers and ABOs among adolescent mothers in South Carolina.

METHODS

This retrospective cross-sectional study derived ZIP Code-level birth statistics from mothers aged 10-19 in South Carolina using 2013-2017 statewide birth certificate data. ABOs included preterm birth and/or low birthweight. Provider distance was calculated between an obstetric provider's ZIP Code tabulated area (ZCTA) centroid and a maternal resident's ZCTA centroid. Descriptive statistics and weighted generalized linear regression were conducted.

RESULTS

Mean provider distances to obstetric providers were similar between urban (11.76 miles) and rural adolescent mothers (12.04 miles). An increase in provider distance, on average, was associated with a decrease in ABO rates (-0.79, p= .0038); however, rural-urban differences were found. Living in a rural ZCTA was associated with a decrease in ABOs (4.94%, p = .0043). Urban ZCTAs showed a U-shaped association with provider distance, with ABO rates decreasing until approximately 17 miles away from a provider and then increasing.

CONCLUSION

Rural adolescent mothers with greater distance to providers had lower ABO rates, while, in urban ZCTAs, provider distance over 17 miles was associated with higher ABO rates. Understanding what mitigates the effects of driving distance on ABOs in rural South Carolina would help inform future policy planning in underserved communities.

Using space-time cube to analyze trends in adverse birth outcomes and maternal characteristics in Massachusetts, USA

Rates of preterm births (< 37 gestational weeks) and low birthweight (≤  2500 g) are rising throughout the United States. This study uses singleton live birth data, Empirical Bayes approach, space-time cube and Mann-Kendall statistic to evaluate temporal trends in these adverse birth outcomes (ABO) and maternal characteristics over 15 years (2000-2014) at the census tract level for non-Hispanic white and black women in Massachusetts. In addition to analyzing trends for each variable individually, the study analyzes spatial coincidence of trends to determine which maternal characteristics exhibited trends that most strongly correlated with the ABO trends. The 15-year average rate of ABO was 7.34% for white women, and 12.05% for black women. Results show that more census tracts exhibited an increasing trend than decreasing trend in birth outcomes and in several maternal characteristics for both races (gestational and chronic hypertension, gestational diabetes, and previous preterm birth). Study identified 52 census tracts concurrently experiencing an increasing trend in ABO and in four maternal characteristics for black women, indicating that multiple negative trends in health outcomes are concentrated at the same location creating a potential for even more adverse outcomes in the future. This study provides a novel, spatially explicit analytical framework based on Empirical Bayes rates and space-time cube, which could be extended to analyze trends in other health outcomes at various spatial scales.

SUPPLEMENTARY INFORMATION

The online version supplementary material available at 10.1007/s10708-021-10382-w.

Maternal proximity to Central Appalachia surface mining and birth outcomes

Supplemental Digital Content is available in the text.

Maternal residency in Central Appalachia counties with coal production has been previously associated with increased rates of low birth weight (LBW). To refine the relationship between surface mining and birth outcomes, this study employs finer spatiotemporal estimates of exposure.

Racial and geographic variation in effects of maternal education and neighborhood-level measures of socioeconomic status on gestational age at birth: Findings from the ECHO cohorts

Preterm birth occurs at excessively high and disparate rates in the United States. In 2016, the National Institutes of Health (NIH) launched the Environmental influences on Child Health Outcomes (ECHO) program to investigate the influence of early life exposures on child health. Extant data from the ECHO cohorts provides the opportunity to examine racial and geographic variation in effects of individual- and neighborhood-level markers of socioeconomic status (SES) on gestational age at birth. The objective of this study was to examine the association between individual-level (maternal education) and neighborhood-level markers of SES and gestational age at birth, stratifying by maternal race/ethnicity, and whether any such associations are modified by US geographic region. Twenty-six ECHO cohorts representing 25,526 mother-infant pairs contributed to this disseminated meta-analysis that investigated the effect of maternal prenatal level of education (high school diploma, GED, or less; some college, associate's degree, vocational or technical training [reference category]; bachelor's degree, graduate school, or professional degree) and neighborhood-level markers of SES (census tract [CT] urbanicity, percentage of black population in CT, percentage of population below the federal poverty level in CT) on gestational age at birth (categorized as preterm, early term, full term [the reference category], late, and post term) according to maternal race/ethnicity and US region. Multinomial logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CIs). Cohort-specific results were meta-analyzed using a random effects model. For women overall, a bachelor's degree or above, compared with some college, was associated with a significantly decreased odds of preterm birth (aOR 0.72; 95% CI: 0.61-0.86), whereas a high school education or less was associated with an increased odds of early term birth (aOR 1.10, 95% CI: 1.00-1.21). When stratifying by maternal race/ethnicity, there were no significant associations between maternal education and gestational age at birth among women of racial/ethnic groups other than non-Hispanic white. Among non-Hispanic white women, a bachelor's degree or above was likewise associated with a significantly decreased odds of preterm birth (aOR 0.74 (95% CI: 0.58, 0.94) as well as a decreased odds of early term birth (aOR 0.84 (95% CI: 0.74, 0.95). The association between maternal education and gestational age at birth varied according to US region, with higher levels of maternal education associated with a significantly decreased odds of preterm birth in the Midwest and South but not in the Northeast and West. Non-Hispanic white women residing in rural compared to urban CTs had an increased odds of preterm birth; the ability to detect associations between neighborhood-level measures of SES and gestational age for other race/ethnic groups was limited due to small sample sizes within select strata. Interventions that promote higher educational attainment among women of reproductive age could contribute to a reduction in preterm birth, particularly in the US South and Midwest. Further individual-level analyses engaging a diverse set of cohorts are needed to disentangle the complex interrelationships among maternal education, neighborhood-level factors, exposures across the life course, and gestational age at birth outcomes by maternal race/ethnicity and US geography.

Maternal Morbidity and Mortality: Are We Getting to the "Heart" of the Matter?

Cardiovascular disease (CVD), including hypertensive disorders of pregnancy (HDP) and peripartum cardiomyopathy, is a leading cause of pregnancy-related death in the United States. Women who are African American or American Indian/Alaskan Native, have HDP, are medically underserved, are older, or are obese have a major risk for the onset and/or progression of CVD during and after pregnancy. Paradoxically, women with no preexisting chronic conditions or risk factors also experience significant pregnancy-related cardiovascular (CV) complications. The question remains whether substantial physiologic stress on the CV system during pregnancy reflected in hemodynamic, hematological, and metabolic changes uncovers subclinical prepregnancy CVD in these otherwise healthy women. Equally important and similarly understudied is the concept that women's long-term CV health could be detrimentally affected by adverse pregnancy outcomes, such as preeclampsia, gestational hypertension, and diabetes, and preterm birth. Thus, a critical life span perspective in the assessment of women's CV risk factors is needed to help women and health care providers recognize and appreciate not only optimal CV health but also risk factors present before, during, and after pregnancy. In this review article, we highlight new advancements in understanding adverse, pregnancy-related CV conditions and will discuss promising strategies or interventions for their prevention, diagnosis, and treatment.

Trends in Preterm Delivery among Singleton Gestations with Critical Congenital Heart Disease

OBJECTIVE

To examine state-wide population trends in preterm delivery of children with critical congenital heart disease (CHD) over an 18-year period. We hypothesized that, coincident with early advancements in prenatal diagnosis, preterm delivery initially increased compared with the general population, and more recently has decreased.

STUDY DESIGN

Data from the Texas Public Use Data File 1999-2016 was used to evaluate annual percent preterm delivery (<37 weeks) in critical CHD (diagnoses requiring intervention at <1 year of age). We first evaluated for pattern change over time using joinpoint segmented regression. Trends in preterm delivery were then compared with all Texas livebirths. We then compared trends examining sociodemographic covariates including race/ethnicity, sex, and neighborhood poverty levels.

RESULTS

Of 7146 births with critical CHD, 1339 (18.7%) were delivered preterm. The rate of preterm birth increased from 1999 to 2004 (a mean increase of 1.69% per year) then decreased between 2005 and 2016 (a mean decrease of -0.41% per year). This represented a faster increase and then a similar decrease to that noted in the general population. Although the greatest proportion of preterm births occurred in newborns of Hispanic ethnicity and non-Hispanic black race, newborns with higher neighborhood poverty level had the most rapidly increasing rate of preterm delivery in the first era, and only a plateau rather than decrease in the latter era.

CONCLUSIONS

Rates of preterm birth for newborns with critical CHD in Texas first were increasing rapidly, then have been decreasing since 2005.

Contraceptive use in Appalachian women who use drugs and were recruited from rural jails

This study describes a secondary data analysis of contraceptive use across the lifetime and within the six months prior to incarceration in a sample of 400 currently incarcerated women recruited from rural, Appalachian jails, who were using drugs prior to incarceration. Phase 1 (baseline) data from an NIH funded study were used to examine rates of contraceptive use, reasons for nonuse of condoms, and correlates of condom use. Results indicate that the majority (96.5%) of respondents reported lifetime use of contraceptives, and most (70.5%) had a history of using multiple methods, with male condoms, oral contraceptive pills, and contraceptive injections being the most commonly used methods. Almost 69% of respondents reported nonuse of contraceptives within the last six months, despite high rates of involvement in risky, intimate male partnerships prior to incarceration. Contraceptive use was found to be historically acceptable in this sample, in stark contrast to rates of use within the last six months prior to incarceration, suggesting that reproductive justice-informed, social work interventions to help improve current contraceptive use are warranted as a harm-reduction approach.

Ethnicity and Low Birth Weight: Inequalities Between Ethnic Minorities and the Predominant Mestizo Population, Colombia, 2008-2014

Low birth weight (LBW) is a global problem that annually affects nearly 20 million children, 96% of these in developing countries. According to the WHO, the poorest and the ethnic minorities are the groups most affected by this indicator. A cross-sectional study of the database of all newborns officially registered in Colombia in 2008-2014 was done. While dichotomizing the mestizo population and ethnic minorities (Afro-descendants, indigenous, ROM), normal and low birth weight was used as the dependent variable and ethnicity as the explanatory variable. Other variables of the parents and the newborns were used as covariates. To assess associations, bivariate and multivariate logistic regression analyses were performed. The incidence of LBW among newborns registered in Colombia fluctuated at around 9%. Among the ethnic minorities, the probability of LBW, adjusted for other variables, was significantly higher (OR 1.07, 95% CI 1.05-1.08) than among mestizos. A significantly higher risk of LBW to newborns in the ethnic minorities' group, and those with unfavorable socioeconomic conditions, was found.

Persisting inequalities in birth outcomes related to neighbourhood deprivation

INTRODUCTION

Health inequalities can be observed in early life as unfavourable birth outcomes. Evidence indicates that neighbourhood socioeconomic circumstances influence health. However, studies looking into temporal trends in inequalities in birth outcomes including neighbourhood socioeconomic conditions are scarce. The aim of this work was to study how inequalities in three different key birth outcomes have changed over time across different strata of neighbourhood deprivation.

METHODS

Nationwide time trends ecological study with area-level deprivation in quintiles as exposure. The study population consisted of registered singleton births in the Netherlands 2003-2017 between 24 and 41 weeks of gestation. Outcomes used were perinatal mortality, premature birth and small for gestational age (SGA). Absolute rates for all birth outcomes were calculated per deprivation quintile. Time trends in birth outcomes were examined using logistic regression models. To investigate relative inequalities, rate ratios for all outcomes were calculated per deprivation quintile.

RESULTS

The prevalence of all unfavourable birth outcomes decreased over time: from 7.2 to 4.1 per 1000 births for perinatal mortality, from 61.8 to 55.6 for premature birth, and from 121.9 to 109.2 for SGA. Inequalities in all birth outcomes have decreased in absolute terms, and the decline was largest in the most deprived quintile. Time trend analyses confirmed the overall decreasing time trends for all outcomes, which were significantly steeper for the most deprived quintile. In relative terms however, inequalities remained fairly constant.

CONCLUSION

In absolute terms, inequalities in birth outcomes by neighbourhood deprivation in the Netherlands decreased between 2003 and 2017. However, relative inequalities remained persistent.

Socioeconomic gradients of adverse birth outcomes and related maternal factors in rural and urban Alberta, Canada: a concentration index approach

OBJECTIVE

Using a summary measure of health inequalities, this study evaluated the distribution of adverse birth outcomes (ABO) and related maternal risk factors across area-level socioeconomic status (SES) gradients in urban and rural Alberta, Canada.

DESIGN

Cross-sectional study using a validated perinatal clinical registry and an area-level SES.

SETTING

The study was conducted in Alberta, Canada. Data about ABO and related maternal risk factors were obtained from the Alberta Perinatal Health Program between 2006 and 2012. An area-level SES index derived from census data (2006) was linked to the postal code at delivery.

PARTICIPANTS

Women (n=3 30 957) having singleton live births with gestational age ≥22 weeks.

PRIMARY AND SECONDARY OUTCOME MEASURES

We estimated concentration indexes to assess inequalities across SES gradients in both rural and urban areas (CIdx_R and CIdx_U, respectively) for spontaneous preterm birth (PTB), small for gestational age (SGA), large for gestational age (LGA), gestational hypertension, gestational diabetes, smoking and substance use during pregnancy and pre-pregnancy weight >91 kg.

RESULTS

The highest health inequalities disfavouring low SES groups were identified for substance abuse and smoking in rural areas (CIdx_R-0.38 and -0.23, respectively). Medium inequalities were identified for LGA (CIdx_R-0.08), pre-pregnancy weight >91 kg (CIdx_R-0.07), substance use (CIdx_U-0.15), smoking (CIdx_U-0.14), gestational diabetes (CIdx_U-0.10) and SGA (CIdx_U-0.07). Low inequalities were identified for PTB (CIdx_R-0.05; CIdx_U-0.05) and gestational diabetes (CIdx_R-0.04). Inequalities disfavouring high SES groups were identified for gestational hypertension (CIdx_R+0.04), SGA (CIdx_R+0.03) and LGA (CIdx_U+0.03).

CONCLUSIONS

ABO and related maternal risk factors were unequally distributed across the socioeconomic gradient in urban-rural settings, with the greatest concentrations in lower SES groups of rural areas. Future research is needed on underlying mechanisms driving SES gradients in perinatal health across the rural-urban spectrum.

Maternal and birth cohort studies in the Gulf Cooperation Council countries: a systematic review and meta-analysis

BACKGROUND

We systematically reviewed and chronicled exposures and outcomes measured in the maternal and birth cohort studies in the Gulf Cooperation Council (GCC) countries and quantitatively summarized the weighted effect estimates between maternal obesity and (1) cesarean section (CS) and (2) fetal macrosomia.

METHODS

We searched MEDLINE-PubMed, Embase, Cochrane Library, Scopus, and Web of Science electronic databases up to 30 June 2019. We considered all maternal and birth cohort studies conducted in the six GCC countries (Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and United Arab Emirates (UAE)). We categorized cohort studies on the basis of the exposure(s) (anthropometric, environmental, medical, maternal/reproductive, perinatal, or socioeconomic) and outcome(s) (maternal or birth) being measured. Adjusted weighted effect estimates, in the form of relative risks, between maternal obesity and CS and fetal macrosomia were generated using a random-effects model.

RESULTS

Of 3502 citations, 81 published cohort studies were included. One cohort study was in Bahrain, eight in Kuwait, seven in Qatar, six in Oman, 52 in Saudi Arabia, and seven in the UAE. Majority of the exposures studied were maternal/reproductive (65.2%) or medical (39.5%). Birth and maternal outcomes were reported in 82.7% and in 74.1% of the cohort studies, respectively. In Saudi Arabia, babies born to obese women were at a higher risk of macrosomia (adjusted relative risk (aRR), 1.15; 95% confidence interval (CI), 1.10-1.20; I2 = 50%) or cesarean section (aRR, 1.21; 95% CI, 1.15-1.26; I2 = 62.0%). Several cohort studies were only descriptive without reporting the magnitude of the effect estimate between the assessed exposures and outcomes.

CONCLUSIONS

Cohort studies in the GCC have predominantly focused on reproductive and medical exposures. Obese pregnant women are at an increased risk of undergoing CS delivery or macrosomic births. Longer-term studies that explore a wider range of environmental and biological exposures and outcomes relevant to the GCC region are needed.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42017068910.

Association between elevated placental polycyclic aromatic hydrocarbons (PAHs) and PAH-DNA adducts from Superfund sites in Harris County, and increased risk of preterm birth (PTB)

The preterm birth (PTB) rate in Harris County, Texas, exceeds the U.S. rate (11.4% vs.9.6%), and there are 15 active Superfund sites in Harris County. Polycyclic aromatic hydrocarbons (PAHs) are contaminants of concern (COC) at Superfund sites across the nation. In this investigation, we tested the hypothesis that higher levels of exposure to PAHs and PAH-DNA adducts in placenta of women living near Superfund sites contribute to the increased rate of PTBs. Levels of benzo[a]pyene (BP), benzo[b]fluorene (BbF) and dibenz[a,h]anthracene (DBA), were higher in placentae from preterm deliveries compared with term deliveries in women living near Superfund sites, whereas this was not the case for women living in non-Superfund site areas. Among the PAHs, DBA levels were significantly higher than BP or BbF, and DBA levels were inversely correlated with gestational age at delivery and birth weight. Bulky PAH-DNA adducts are more prevalent in placental tissue from individuals residing near Superfund sites. Expression of Ah receptor (AHR) and NF-E2-related factor 2 (NRF2) was decreased in preterm deliveries in subjects residing near Superfund sites. Unbiased metabolomics revealed alterations in pathways involved in pentose phosphate, inositol phosphate and starch and sucrose metabolism in preterm subjects in Superfund site areas. In summary, this is the first report showing an association between PAH levels, DNA adducts, and modulation of endogenous metabolic pathways with PTBs in subjects residing near Superfund sites, and further studies could lead to novel strategies in the understanding of the mechanisms by which PAHs contribute to PTBs in women.

Influence of the spatial resolution of the exposure estimate in determining the association between heat waves and adverse health outcomes

BACKGROUND

Area-level estimates of temperature may lead to exposure misclassification in studies examining associations between heat waves and health outcomes. Our study compared the association between heat waves and preterm birth (PTB) or non-accidental death (NAD) using exposure metrics at varying levels of spatial resolution: ZIP codes, 12.5 km, and 1 km.

METHOD

Using geocoded residential addresses on birth (1990-2010) and death (1997-2010) records from Alabama, USA, we implemented a time-stratified case-crossover design to examine the association between heat waves and PTB or NAD. ZIP code- and 12.5 km heat wave indices (HIs) were derived using air temperatures from Phase 2 of the North American Land Data Assimilation System (NLDAS-2). We downscaled NLDAS-2 data, using land surface temperatures (LST) from the Moderate Resolution Imaging Spectroradiometer (MODIS) product, to estimate fine spatial resolution HIs (1 km).

RESULTS

The association between heat waves and PTB or NAD was significant and positive using ZIP code-, 12.5 km, and 1 km exposure metrics. Moreover, results show that these three-exposure metric analyses produced similar effect estimates. Urban heat islands were evident with the 1 km metric. When analyses were stratified by rurality, we found associations in urban areas were more positive than in rural areas.

CONCLUSIONS

Comparing results of models with a varying spatial resolution of the exposure metric allows for examination of potential bias associated with exposure misclassification.

Impacts of high temperature on adverse birth outcomes in Seoul, Korea: Disparities by individual- and community-level characteristics

BACKGROUND

Few studies have examined temperature's effect on adverse birth outcomes and relevant effect modifiers.

OBJECTIVES

We investigated associations between heat and adverse birth outcomes and how individual and community characteristics affect these associations for Seoul, Korea, 2004-2012.

METHODS

We applied logistic regression to estimate associations between heat index during pregnancy, 4 weeks before delivery, and 1 week before delivery and risk of preterm birth and term low birth weight. We investigated effect modification by individual (infant's sex, mother's age, and mother's educational level) and community characteristics (socioeconomic status (SES) and percentage of green areas near residence at the gu level, which is similar to borough in Western countries). We also evaluated associations by combinations of individual- and community-level SES.

RESULTS

Heat exposure during whole pregnancy was significantly associated with risk of preterm birth. An interquartile (IQR) increase (5.5 °C) in heat index during whole pregnancy was associated with an odds ratio (OR) of 1.033 (95% CI 1.005, 1.061) with NO2 adjustment, and 1.028 (95% CI 0.998, 1.059) with PM10 adjustment, for preterm birth. We also found significant associations with heat exposure during 4 weeks before delivery and 1 week before delivery on preterm birth. We did not observe significant associations with term low birth weight. Higher risk of heat on preterm birth was associated with some individual characteristics such as infants with younger or older mothers and lower community-level SES. For combinations of individual- and community-level SES, the highest and most significant estimated effect was found for infants with low educated mothers living in low SES communities, with suggestions of effects of both individual-and community-level SES.

CONCLUSIONS

Our findings have implications for evaluating impacts of high temperatures on birth outcomes, estimating health impacts of climate change, and identifying which subpopulations and factors are most relevant for disparities in this association.

Extending the developmental origins of disease model: Impact of preconception stress exposure on offspring neurodevelopment

The concept of the developmental origins of health and disease via prenatal programming has informed many etiologic models of health and development. Extensive experimental research in non-human animal models has revealed the impact of in utero exposure to stress on fetal development and neurodevelopment later in life. Stress exposure, however, is unlikely to occur de novo following conception, and pregnancy health is not independent of the health of the system prior to conception. For these reasons, the preconception period is emerging as an important new focus for research on adverse birth outcomes and offspring neurodevelopment. In this review, we summarize the existing evidence for the role of preconception stress exposure on pregnancy health and offspring neurodevelopment across species and discuss the implications of this model for addressing health disparities in obstetrics and offspring outcomes.

Rural community birth: Maternal and neonatal outcomes for planned community births among rural women in the United States, 2004-2009

BACKGROUND

Approximately 22% of women in the United States live in rural areas with limited access to obstetric care. Despite declines in hospital-based obstetric services in many rural communities, midwifery care at home and in free standing birth centers is available in many rural communities. This study examines maternal and neonatal outcomes among planned home and birth center births attended by midwives, comparing outcomes for rural and nonrural women.

METHODS

Using the Midwives Alliance of North America Statistics Project 2.0 dataset of 18 723 low-risk, planned home, and birth center births, rural women (n = 3737) were compared to nonrural women. Maternal outcomes included mode of delivery (cesarean and instrumental delivery), blood transfusions, severe events, perineal lacerations, or transfer to hospital and a composite (any of the above). The primary neonatal outcome was a composite of early neonatal intensive care unit or hospital admissions (longer than 1 day), and intrapartum or neonatal deaths. Analysis involved multivariable logistic regression, controlling for sociodemographics, antepartum, and intrapartum risk factors.

RESULTS

Rural women had different risk profiles relative to nonrural women and reduced risk of adverse maternal and neonatal outcomes in bivariable analyses. However, after adjusting for risk factors and confounders, there were no significant differences for a composite of maternal (adjusted odds ratio [aOR] 1.05 [95% confidence interval {CI} 0.93-1.19]) or neonatal (aOR 1.13 [95% CI 0.87-1.46]) outcomes between rural and nonrural pregnancies.

CONCLUSION

Among this sample of low-risk women who planned midwife-led community births, no increased risk was detected by rural vs nonrural status.

Association Between Loss of Hospital-Based Obstetric Services and Birth Outcomes in Rural Counties in the United States

IMPORTANCE

Hospital-based obstetric services have decreased in rural US counties, but whether this has been associated with changes in birth location and outcomes is unknown.

OBJECTIVE

To examine the relationship between loss of hospital-based obstetric services and location of childbirth and birth outcomes in rural counties.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study, using county-level regression models in an annual interrupted time series approach. Births occurring from 2004 to 2014 in rural US counties were identified using birth certificates linked to American Hospital Association Annual Surveys. Participants included 4 941 387 births in all 1086 rural counties with hospital-based obstetric services in 2004.

EXPOSURES

Loss of hospital-based obstetric services in the county of maternal residence, stratified by adjacency to urban areas.

MAIN OUTCOMES AND MEASURES

Primary outcomes were county rates of (1) out-of-hospital births; (2) births in hospitals without obstetric units; and (3) preterm births (<37 weeks' gestation).

RESULTS

Between 2004 and 2014, 179 rural counties lost hospital-based obstetric services. Of the 4 941 387 births studied, the mean (SD) maternal age was 26.2 (5.8) years. A mean (SD) of 75.9% (23.2%) of women who gave birth were non-Hispanic white, and 49.7% (15.6%) were college graduates. Rural counties not adjacent to urban areas that lost hospital-based obstetric services had significant increases in out-of-hospital births (0.70 percentage points [95% CI, 0.30 to 1.10]); births in a hospital without an obstetric unit (3.06 percentage points [95% CI, 2.66 to 3.46]); and preterm births (0.67 percentage points [95% CI, 0.02 to 1.33]), in the year after loss of services, compared with those with continual obstetric services. Rural counties adjacent to urban areas that lost hospital-based obstetric services also had significant increases in births in a hospital without obstetric services (1.80 percentage points [95% CI, 1.55 to 2.05]) in the year after loss of services, compared with those with continual obstetric services, and this was followed by a decreasing trend (-0.19 percentage points per year [95% CI, -0.25 to -0.14]).

CONCLUSIONS AND RELEVANCE

In rural US counties not adjacent to urban areas, loss of hospital-based obstetric services, compared with counties with continual services, was associated with increases in out-of-hospital and preterm births and births in hospitals without obstetric units in the following year; the latter also occurred in urban-adjacent counties. These findings may inform planning and policy regarding rural obstetric services.

Maternal and birth cohort studies in the Gulf Cooperation Council countries: protocol for a systematic review and narrative evaluation

INTRODUCTION

Cohort studies have revealed that genetic, socioeconomic, communicable and non-communicable diseases, and environmental exposures during pregnancy may influence the mother and her pregnancy, birth delivery and her offspring. Numerous studies have been conducted in the Gulf Cooperation Council (GCC) countries to examine maternal and birth health. The objectives of this protocol for a systematic review are to systematically review and characterise the exposures and outcomes that have been examined in the mother and birth cohort studies in the GCC region, and to summarise the strength of association between key maternal exposures during pregnancy (ie, body mass index) and different health-related outcomes (ie, mode of birth delivery). The review will then synthesise and characterise the consequent health implications and will serve as a platform to help identify areas that are overlooked, point out limitations of studies and provide recommendations for future cohort studies.

METHODS AND ANALYSIS

Medline, Embase, Cochrane Library and Web of Science electronic databases will be comprehensively searched. Two reviewers will independently screen each study for eligibility, and where discrepancies arise they will be discussed and resolved; otherwise a third reviewer will be consulted. The two reviewers will also independently extract data into a predefined Excel spreadsheet. The included studies will be categorised on the basis of whether the participant is a mother, infant or mother-infant dyad. Outcome variables will be divided along two distinctions: mother or infant. Exposure variables will be divided into six domains: psychosocial, biological, environmental, medical/medical services, maternal/reproductive and perinatal/child. Studies are expected to be of heterogeneous nature; therefore, quantitative syntheses might be limited.

ETHICS AND DISSEMINATION

There is no primary data collection; therefore, ethical review is not necessary. The findings of this review will be disseminated in a peer-reviewed journal and presented at relevant conferences.

PROSPERO REGISTRATION NUMBER

CRD42017068910.

Environmental Health Priorities of Residents and Environmental Health Professionals: Implications for Improving Environmental Health Services in Rural Versus Urban Communities

Previous research has suggested differences between public and professional understanding of the field of environmental health (EH) and the role of EH services within urban and rural communities. This study investigated EH priority differences between 1) rural and urban residents and 2) residents and EH professionals, and presents quantitative and qualitative methods for establishing locality-specific EH priorities. Residents (N = 588) and EH professionals (N = 63) in Alabama identified EH priorities via a phone or online survey. We categorized rurality of participant residences by rural-urban commuting area codes and population density, and tested whether or not EH priorities were different between urban and rural residents. Built environment issues, particularly abandoned houses, and air pollution were high priorities for urban residents-whereas, water and sanitation issues, and paper mill-related pollution were high priorities in rural communities. EH professionals ranked food safety and water and sanitation issues as higher priorities than residents did. Results highlight the importance of urbanicity on environmental risk perception and the utility of simple and inexpensive engagement methods for understanding these differences. Differences between residents and EH professionals suggest improving stakeholder participation in local-level EH decision making might lead to greater awareness of EH services, which might in turn improve support and effectiveness of those services.

Coordinated Care Organizations: Neonatal and Infant Outcomes in Oregon

In 2012, Oregon's Medicaid program implemented a comprehensive accountable care model delivered through coordinated care organizations (CCOs). Because CCOs are expected to improve utilization of services and health outcomes, neonatal and infant outcomes may be important indicators of their impact. Estimating difference-in-differences models, we compared prepost CCO changes in outcomes (e.g., low birth weight, abnormal conditions, 5-minute Apgar score, congenital anomalies, and infant mortality) between Medicaid and non-Medicaid births among 99,924 infants born in Oregon during 2011 and 2013. We further examined differences in the impact of CCOs by ethnicity and rurality. Following CCO implementation the likelihood of low birth weight and abnormal conditions decreased by 0.95% and 1.08%, a reduction of 13.4% and 10.4% compared with the pre-CCO level for Medicaid enrollees, respectively. These reductions could be predictive of lifelong health benefits for infants and lower costs for acute care and are, therefore, important markers of success for the CCO model.

Differences in the pregnancy gestation period and mean birth weights in infants born to Indian, Pakistani, Bangladeshi and white British mothers in Luton, UK: a retrospective analysis of routinely collected data

OBJECTIVE

To compare mean birth weights and gestational age at delivery of infants born to Indian, Pakistani, Bangladeshi and white British mothers in Luton, UK.

DESIGN

Retrospective analysis using routinely recorded secondary data in Ciconia Maternity information System, between 2008 and 2013.

SETTING

Luton, UK.

PARTICIPANTS

Mothers whose ethnicity was recorded as white British, Bangladeshi, Pakistani or Indian and living in Luton, aged over 16, who had a live singleton birth over 24 weeks of gestation were included in the analysis (n=14 871).

OUTCOME MEASURES

Primary outcome measures were mean birth weight and gestational age at delivery.

RESULTS

After controlling for maternal age, smoking, diabetes, gestation age, parity and maternal height and body mass index at booking, a significant difference in infants' mean birth weight was found between white British and Indian, Pakistani and Bangladeshi infants, F(3, 12 287)=300.32, p<0.0001. The partial Eta-squared for maternal ethnicity was η²=0.067. The adjusted mean birth weight for white British infants was found to be 3377.89 g (95% CI 3365.34 to 3390.44); Indian infants, 3033.09 g (95% CI 3038.63 to 3103.55); Pakistani infants, 3129.49 g (95% CI 3114.5 to 3144.48); and Bangladeshi infants, 3064.21 g (95% CI 3041.36 to 3087.06). There was a significant association in preterm delivery found in primipara Indian mothers, compared with Indian mothers (Wald=8.192, df 1, p<0.005).

CONCLUSIONS

Results show important differences in adjusted mean birth weight between Indian, Pakistani, Bangladeshi and white British women. Moreover, an association was found between primipara Indian mothers and preterm delivery, when compared with Pakistani, Bangladeshi and white British women.

Measuring birth outcomes in New York State using a multidimensional approach

OBJECTIVE

Poorer birth outcomes in the United States and New York State (NYS) remain a significant public health concern. The objectives of this study were to assess the effect of common and unique demographic, socioeconomic, and health services predictors on low birth weight (LBW), moderately LBW, very low birth weight (VLBW), and extremely low birth weight (ELBW) in NYS counties and to recommend policies that address unique differences at the county level.

METHODS

Secondary data were collected for each of the 62 counties in NYS. Using a multidimensional approach, common and unique factors for LBW, moderately LBW, VLBW, and ELBW among NYS counties were evaluated. Correlations and multiple regression analyses were conducted for each of the outcome variables.

RESULTS

Late prenatal care was the only significant predictor across all measures of poorer birth outcomes in NYS counties. Out-of-wedlock births, Medicaid Obstetrical Maternal Service providers, rural location, early prenatal care, advanced maternal age, and teen pregnancy rate were significant predictors, but not for all measures.

CONCLUSIONS

Findings highlight the need to move beyond the number of providers when analyzing birth outcomes at the county level. Programs that support teens and women of all ages and marital status need to be expanded to curb poorer birth outcomes that take a heavy human and financial toll in NYS.

Preterm birth and its associations with residence and ambient vehicular traffic exposure

BACKGROUND

Preterm birth (PTB) is a multifactorial disorder, and air pollution has been suggested to increase the risk of occurrence. However, large population studies controlling for multiple exposure measures in high-density settings with established commuter patterns are lacking.

OBJECTIVE

We performed a geospatial analysis with the use of a publicly available database to identify whether residence during pregnancy, specifically with regard to exposure to traffic density and mobility in urban and suburban neighborhoods, may be a contributing risk factor for premature delivery.

STUDY DESIGN

In our cohort study, we analyzed 9004 pregnancies with as many as 4900 distinct clinical and demographic variables from Harris County, Texas. On the basis of primary residency and occupational zip code information, geospatial analysis was conducted. Data on vehicle miles traveled (VMT) and percentages of inhabitants traveling to work were collected at the zip code level and additionally grouped by the three recognized regional commuter loop high-density thoroughfares resulting from two interstate/highway belts (inner, middle, and outer loops). PTB was categorized as late (34 1/7 to 36 6/7 weeks) and early PTB (22 1/7 to 33 6/7 weeks), and unadjusted odds ratios (OR) and adjusted ORs were ascribed.

RESULTS

PTB prevalence in our study population was 10.1% (6.8% late and 3.3% early preterm), which is in accordance with our study and other previous studies. Prevalence of early PTB varied significantly between the regional commuter loop thoroughfares [OR for inner vs outer loop: 0.58 (95% confidence interval, 0.39-0.87), OR for middle vs outer loop, 0.74 (0.57-0.96)]. The ORs for PTB and early PTB were shown to be lower in gravidae from neighborhoods with the highest VMT/acre [OR for PTB, 0.82 (0.68-0.98), OR for early PTB, 0.78 (0.62-0.98)]. Conversely, risk of PTB and early PTB among subjects living in neighborhoods with a high percentage of inhabitants traveling to work over a greater distance demonstrated a contrary tendency [OR for PTB, 1.18 (1.03-1.35), OR for early PTB, 1.48 (1.17-1.86)]. In logistic regression models, the described association between PTB and residence withstood and could not be explained by differences in maternal age, gravidity or ethnicity, tobacco use, or history of PTB.

CONCLUSION

While PTB is of multifactorial origin, the present study shows that community-based risk factors (namely urban/suburban location, differences in traffic density exposure, and need for traveling to work along high-vehicle density thoroughfares) may influence risk for PTB. Further research focusing on previously unrecognized community-based risk factors may lead to innovative future prevention measures.

Association of neighborhood context with offspring risk of preterm birth and low birthweight: A systematic review and meta-analysis of population-based studies

Findings from studies investigating associations of residential environment with poor birth outcomes have been inconsistent. In a systematic review and meta-analysis, we examined associations of neighborhood disadvantage with preterm birth (PTB) and low birthweight (LBW), and explored differences in relationships among racial groups. Two reviewers searched English language articles in electronic databases of published literature. We used random effects logistic regression to calculate odds ratios (and 95% confidence intervals) relating neighborhood disadvantage with PTB and LBW. Neighborhood disadvantage, most disadvantaged versus least disadvantaged neighborhoods, was defined by researchers of included studies, and comprised of poverty, deprivation, racial residential segregation or racial composition, and crime. We identified 1314 citations in the systematic review. The meta-analyses included 7 PTB and 14 LBW cross-sectional studies conducted in the United States (U.S.). Overall, we found 27% [95%CI: 1.16, 1.39] and 11% [95%CI: 1.07, 1.14] higher risk for PTB and LBW among the most disadvantaged compared with least disadvantaged neighborhoods. No statistically significant association was found in meta-analyses of studies that adjusted for race. In race-stratified meta-analyses models, we found 48% [95%CI: 1.25, 1.75] and 61% [95%CI: 1.30, 2.00] higher odds of PTB and LBW among non-Hispanic white mothers living in most disadvantaged neighborhoods compared with those living in least disadvantaged neighborhoods. Similar, but less strong, associations were observed for PTB (15% [95%CI: 1.09, 1.21]) and LBW (17% [95%CI: 1.10, 1.25]) among non-Hispanic black mothers. Neighborhood disadvantage is associated with PTB and LBW, however, associations may differ by race. Future studies evaluating causal mechanisms underlying the associations, and racial/ethnic differences in associations, are warranted.

Comparing and decomposing the determinants of multiple health outcomes in southern and northeastern US states using county data

Objectives

To investigate whether regional health disparities could explain health outcome differences between US regions.

Methods

The 2010–2012 County Level Raking database, which contains measures on health outcomes and factors for the US states, are used in this study. First, a regional comparison of the determinants of various health outcome measures (premature death rates, low birth weight rate and mean unhealthy days) is undertaken. Next, using the Blinder–Oaxaca decomposition method, the differences in health outcomes are partitioned into the portion explained by regional health factor endowments and the portion unexplained.

Key findings

Obesity rate and access to care determinants impact strongly each region's health outcomes. Half of the differences in clinically assessed (premature death rates and low birth weight rates) measures are unexplained by health endowments. The explained portion for the self-assessed (unhealthy days) outcomes is small.

Conclusions

Study findings both justify the imperatives of accounting for regional variations in order to strengthen policy inferences of research findings and suggest the prevalence of regional disparities in health outcomes. It is important to focus on region-specific preventive care. More effective public education and information strategies raising population awareness to the health hazards of obesity are in order. Greater access to various health services personnel should be provided to the relevant population. Implications are discussed for pharmaceutical care.

Socioeconomic Disparities in Adverse Birth Outcomes in Urban and Rural Contexts: a French Mother-Child Cohort

BACKGROUND

Although adverse birth outcomes have been associated with neighbourhood deprivation in urban areas, few studies have addressed this issue in rural zones. This study examines whether associations between neighbourhood deprivation and adverse birth outcomes differ in urban and rural contexts, while taking individual characteristics and spatial accessibility of prenatal care (SAPC) into account.

METHODS

Pregnant women from a French mother-child cohort were recruited from 2002 to 2006 in Brittany. Their residential addresses were geocoded into their census blocks (the finest geographical resolution available). Deprivation was assessed at the same neighbourhood level. Models to assess the associations of deprivation, stratified by urban/rural status, with preterm delivery (PTD), with small for gestational age birth weight (SGA) and with small for gestational age head circumference at birth (SHC), estimated odds ratios (ORs), adjusted for maternal socioeconomic characteristics and SAPC.

RESULTS

This study considered 2929 liveborn singleton pregnancies from 780 census blocks. Neighbourhood deprivation was associated with increased risks of SGA and SHC (P trend < 0.01 and 0.03 respectively), only among mothers residing in rural areas. Neighbourhood deprivation had statistically significantly heterogeneous effects on SGA and SHC according to the urban/rural status of maternal residence.

CONCLUSION

These findings suggest that neighbourhood deprivation affects fetal growth differentially in urban and rural areas and that SAPC does not seem to be responsible for this difference. Comparison of these findings with the literature requires caution in the conceptualisation of urban and rural settings.

Factors for Preterm Births in Germany - An Analysis of Representative German Data (KiGGS)

Introduction: Preterm birth is a global scourge, the leading cause of perinatal mortality and morbidity. This study set out to identify the principal risk factors for preterm birth, based on the German Health Interview and Examination Survey for Children and Adolescents (KiGGS). A range of possible factors influencing preterm birth were selected for inclusion in the questionnaire, covering factors such as gender, national origin, immigrant background, demography, living standard, family structure, parental education and vocational training. Methods: All data were taken from the aforementioned KiGGS survey conducted between 2003 and 2006. A total of 17 641 children and adolescents (8656 girls and 8985 boys) drawn from 167 German towns and municipalities deemed to be representative of the Federal Republic of Germany were included in the study. Gestational age at birth was available for 14 234 datasets. The questionnaire included questions from the following areas as possible factors influencing preterm birth: gender, national origins, immigrant background, demography, living standard, family structure, parental education and vocational training. Results: The preterm birth rate was 11.6 %, higher than that of other national statistical evaluations. Around 57.4 % of multiple pregnancies and 10 % of singleton pregnancies resulted in preterm delivery. Multiple pregnancy was found to be the most important risk factor (OR 13.116). With regard to national origins and immigration background, mothers from Turkey, the Middle East, and North Africa had a higher incidence of preterm birth. Preterm birth was more prevalent in cities and large towns than in small towns and villages. Conclusion: Risk factors associated with preterm birth were identified. These should help with the early identification of pregnant women at risk. The preterm birth rate in our survey was higher than that found in other national statistical evaluations based on process data. More than half of all multiple pregnancies ended in preterm birth.

A cost comparison of travel models and behavioural telemedicine for rural, Native American populations in New Mexico

OBJECTIVE

The purpose of this study was to model the cost of delivering behavioural health services to rural Native American populations using telecommunications and compare these costs with the travel costs associated with providing equivalent care.

METHODS

Behavioural telehealth costs were modelled using equipment, transmission, administrative and IT costs from an established telecommunications centre. Two types of travel models were estimated: a patient travel model and a physician travel model. These costs were modelled using the New Mexico resource geographic information system program (RGIS) and ArcGIS software and unit costs (e.g. fuel prices, vehicle depreciation, lodging, physician wages, and patient wages) that were obtained from the literature and US government agencies.

RESULTS

The average per-patient cost of providing behavioural healthcare via telehealth was US$138.34, and the average per-patient travel cost was US$169.76 for physicians and US$333.52 for patients. Sensitivity analysis found these results to be rather robust to changes in imputed parameters and preliminary evidence of economies of scale was found.

CONCLUSION

Besides the obvious benefits of increased access to healthcare and reduced health disparities, providing behavioural telehealth for rural Native American populations was estimated to be less costly than modelled equivalent care provided by travelling. Additionally, as administrative and coordination costs are a major component of telehealth costs, as programmes grow to serve more patients, the relative costs of these initial infrastructure as well as overall per-patient costs should decrease.

Modulation of prenatal stress via docosahexaenoic acid supplementation: implications for child mental health

Pregnant women living in poverty experience chronic and acute stressors that may lead to alterations in circulating glucocorticoids. Experimental evidence from animal models and correlational studies in humans support the hypothesis that prenatal exposure to high levels of glucocorticoids can negatively affect the developing fetus and later emotional and behavioral regulation in the offspring. In this integrative review, recent findings from research in psychiatry, obstetrics, and animal and human experimental studies on the role of docosahexaenoic acid in modulation of the stress response and brain development are discussed. The potential for an emerging field of nutritionally based perinatal preventive interventions for improving offspring mental health is described. Prenatal nutritional interventions may prove to be effective approaches to reducing common childhood mental disorders.

Environmental variables as potential modifiable risk factors of preterm birth in Philadelphia, PA

OBJECTIVE

To examine whether variation in neighborhood context is associated with preterm birth (PTB) outcomes and gestational age (GA) at delivery in Philadelphia, and to determine whether these associations might persist when considering relevant individual-level variables.

STUDY DESIGN

We analyzed individual-level data collected for a prospective cohort study of singleton pregnancies with preterm labor. We merged block-group level data to each individual's home address. Unadjusted analyses were performed to determine the association between block-group variables and individual-level outcomes. Block-group variables identified as potential risk factors were incorporated into multivariable individual-level models to determine significance.

RESULTS

We analyzed data for 817 women. The prevalence of PTB <37 weeks was 41.5%. Although in unadjusted analyses several block-group variables were associated with PTB and GA at delivery, none retained significance in individual-level multivariable models.

CONCLUSION

Block-group level data were not associated with PTB outcomes or GA at delivery in Philadelphia.

Association between fatty acid supplementation and prenatal stress in African Americans: a randomized controlled trial

OBJECTIVE

To test the association between docosahexaenoic acid (DHA) supplementation and perceived stress and cortisol response to a stressor during pregnancy in a sample of African American women living in low-income environments.

METHODS

Sixty-four African American women were enrolled at 16-21 weeks of gestation. Power calculations were computed using published standard deviations for the Perceived Stress Scale and the Trier Social Stress Test. Participants were randomized to either 450 mg per day of DHA (n=43) or placebo (n=21). At baseline and at 24 and 30 weeks of gestation, perceived stress was assessed by self-report. Cortisol response to a controlled stressor, the Trier Social Stress Test was measured from saliva samples collected upon arrival to the laboratory and after the completion of the Trier Social Stress Test.

RESULTS

Women in the DHA supplementation group reported lower levels of perceived stress at 30 weeks of gestation, controlling for depression and negative life events (mean 27.4 compared with 29.5, F [3, 47] 5.06, P=.029, Cohen's d=0.65). Women in the DHA supplementation had lower cortisol output in response to arriving to the laboratory and a more modulated response to the stressor (F [1.78, 83.85] 6.24, P=.004, Cohen's d=0.76).

CONCLUSION

Pregnant women living in urban low-income environments who received DHA reported reduced perceived stress and lower levels of stress hormones in the third trimester. Docosahexaenoic acid supplementation may be a method for attenuating the effects of maternal stress during late pregnancy and improving the uterine environment with regard to fetal exposure to glucocorticoids.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, www.clinicaltrials.gov, NCT01158976.

Epidemiologic factors and urogenital infections associated with preterm birth in a midwestern U.S. population

OBJECTIVE

To correlate epidemiologic factors with urogenital infections associated with preterm birth.

METHODS

Pregnant women were sequentially included from four Wisconsin cohorts: large urban, midsize urban, small city, and rural city. Demographic, clinical, and current pregnancy data were collected. Cervical and urine specimens were analyzed by microscopy, culture, and polymerase chain reaction for potential pathogens.

RESULTS

Six hundred seventy-six women were evaluated. Fifty-four (8.0%) had preterm birth: 12.1% (19/157) large urban, 8.8% (15/170) midsize urban, 9.4% (16/171) small city, and 2.3% (4/178) rural city. Associated host factors and infections varied significantly among sites. Urogenital infection rates, especially Mycoplasma hominis and Ureaplasma parvum, were highest at the large urban site. Large urban site, minority ethnicity, multiple infections, and certain historical factors were associated with preterm birth by univariable analysis. By multivariable analysis, preterm birth was associated with prior preterm birth (adjusted odds ratio [aOR] 2.76, 95% confidence interval [CI] 1.27-6.02) and urinary tract infection (aOR 2.62, 95% CI 1.32-519), and negatively associated with provider-assessed good health (aOR 0.42, 95% CI 0.23-0.76) and group B streptococcal infection treatment (surrogate for health care use) (aOR 0.38, 95% CI 0.15-.99). Risk and protective factors were similar for women with birth at less than 35 weeks, and additionally associated with M hominis (aOR 3.6, 95% CI 1.4-9.7).

CONCLUSION

These measured differences among sites are consistent with observations that link epidemiologic factors, both environmental and genetic, with minimally pathogenic vaginal bacteria, inducing preterm birth, especially at less than 35 weeks of gestation.