Factors associated with residential mobility during pregnancy

Effects of US state preemption laws on infant mortality

Studies show that raising the minimum wage in a US state above the federal minimum wage can reduce infant mortality rates in those states. Some states have raised their minimum wage in recent decades, while many others did not, and have prohibited local authorities from doing so by enacting preemption laws. This study investigates how the recent emergence of state preemption laws that remove local authority to raise the minimum wage has affected infant mortality rates. Using county- and state- level data spanning 2001 through 2018, this study models infant mortality rates as a function of minimum wage levels, controlling for confounders. The estimated model, combined with information on the timing, location, and level of preempted minimum wages, is then used to estimate the number of infant deaths that occurred in 2018 that could be attributed to state preemption of local minimum wage increases. In the 9 largest (pop. > 250,000) metro counties most directly affected by state preemption, we estimate that in 2018, 25 infant deaths were attributable to preemption. This equates to a 5.4% reduction in these counties' infant mortality rate. When considering all large metro counties in preemption states, as many as 605 infant deaths could be attributed to preemption. State preemption laws that remove local authority to enact health-promoting legislation, such as minimum wage increases, are a significant threat to population health. The growing tide of these laws, particularly since 2010, may be contributing to recent troubling trends in US life expectancy.

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.

Residence change during the first trimester of pregnancy and adverse birth outcomes

BACKGROUND

There are few published studies evaluating the impact of perinatal residence change on infant outcomes and whether these associations differ by socioeconomic status.

METHODS

We conducted a population-based cohort study using Washington State birth certificate data from 2007 to 2014 to assess whether women who moved during the first trimester of pregnancy (n=28 011) had a higher risk of low birth weight, preterm birth and small for gestational age than women who did not move during the first trimester (n=112 367). 'Non-first-trimester movers' were frequency matched 4:1 to movers by year. We used generalised linear models to calculate risk ratios and risk differences adjusted for maternal age, race, marital status, parity, education, smoking, income and insurance payer for the birth. We also stratified analyses by variables related to socioeconomic status to see whether associations differed across socioeconomic strata.

RESULTS

Moving in the first trimester was associated with an increased risk of low birth weight (6.4% vs 4.5%, adjusted risk ratio 1.37 (95% CI 1.29 to 1.45)) and preterm birth (9.1% vs 6.4%, adjusted risk ratio 1.42 (95% CI 1.36 to 1.49)) and a slight increased risk of small for gestational age (9.8% vs 8.7%, adjusted risk ratio 1.09 (95% CI 1.00 to 1.09)). Residence change was associated with low birth weight and preterm birth in all socioeconomic strata.

CONCLUSION

Moving during the first trimester of pregnancy may be a risk factor for adverse birth outcomes in US women. Healthcare providers may want to consider screening for plans to move and offering support.

Using Index of Concentration at the Extremes as Indicators of Structural Racism to Evaluate the Association with Preterm Birth and Infant Mortality-California, 2011-2012

Disparities in adverse birth outcomes for Black women continue. Research suggests that societal factors such as structural racism explain more variation in adverse birth outcomes than individual-level factors and societal poverty alone. The Index of Concentration at the Extremes (ICE) measures spatial social polarization by quantifying extremes of deprived and privileged social groups using a single metric and has been shown to partially explain racial disparities in black carbon exposures, mortality, fatal and non-fatal assaults, and adverse birth outcomes such as preterm birth and infant mortality. The objective of this analysis was to assess if local measures of racial and economic segregation as proxies for structural racism are associated and preterm birth and infant mortality experienced by Black women residing in California. California birth cohort files were merged with the American Community Survey by zip code (2011-2012). The ICE was used to quantify privileged and deprived groups (i.e., Black vs. White; high income vs. low income; Black low income vs. White high income) by zip code. ICE scores range from - 1 (deprived) to 1 (privileged). ICE scores were categorized into five quintiles based on sample distributions of these measures: quintile 1 (least privileged)-quintile 5 (most privileged). Generalized linear mixed models were used to test the likelihood that ICE measures were associated with preterm birth or with infant mortality experienced by Black women residing in California. Black women were most likely to reside in zip codes with greater extreme income concentrations, and moderate extreme race and race + income concentrations. Bivariate analysis revealed that greater extreme income, race, and race + income concentrations increased the odds of preterm birth and infant mortality. For example, women residing in least privileged zip codes (quintile 1) were significantly more likely to experience preterm birth (race + income ICE OR = 1.31, 95% CI = 1.72-1.46) and infant mortality (race + income ICE OR = 1.70, 95% CI = 1.17-2.47) compared to women living in the most privileged zip codes (quintile 5). Adjusting for maternal characteristics, income, race, and race + income concentrations remained negatively associated with preterm birth. However, only race and race + income concentrations remained associated with infant mortality. Findings support that ICE is a promising measure of structural racism that can be used to address racial disparities in preterm birth and infant mortality experienced by Black women in California.