Maternal opioid use disorder and infant mortality in Wisconsin, United States, 2010-2018.

OBJECTIVE: The difference in infant health outcomes by maternal opioid use disorder (OUD) status is understudied. We measured the association between maternal OUD during pregnancy and infant mortality and investigated whether this association differs by infant neonatal opioid withdrawal syndrome (NOWS) or maternal receipt of medication for OUD (MOUD) during pregnancy. METHODS: We sampled 204,543 Medicaid-paid births from Wisconsin, United States (2010-2018). The primary exposure was any maternal OUD during pregnancy. We also stratified this exposure on NOWS diagnosis (no OUD; OUD without NOWS; OUD with NOWS) and on maternal MOUD receipt (no OUD; OUD without MOUD; OUD with <90 consecutive days of MOUD; OUD with 90+ consecutive days of MOUD). Our outcome was infant mortality (death at age <365 days). Demographic-adjusted logistic regressions measured associations with odds ratios (OR) and 95% confidence intervals (CI). RESULTS: Maternal OUD was associated with increased odds of infant mortality (OR 1.43; 95% CI 1.02-2.02). After excluding infants who died <5 days post-birth (i.e., before the clinical presentation of NOWS), regression estimates of infant mortality did not significantly differ by NOWS diagnosis. Likewise, regression estimates did not significantly differ by maternal MOUD receipt in the full sample. CONCLUSIONS: Maternal OUD is associated with an elevated risk of infant mortality without evidence of modification by NOWS nor by maternal MOUD treatment. Future research should investigate potential mechanisms linking maternal OUD, NOWS, MOUD treatment, and infant mortality to better inform clinical intervention.

Infant Mortality in Rural and Nonrural Counties in the United States.

BACKGROUND AND OBJECTIVES: Rural counties have the highest infant mortality rates across the United States when compared with rates in more urban counties. We use a social-ecological framework to explain infant mortality disparities across the rural-urban continuum. METHODS: We created a cohort of all births in the United States linked to infant death records for 2014 to 2016. Records were linked to county-level data from the Area Health Resources File and the American Community Survey and classified using the National Center for Health Statistics Urban-Rural Classification Scheme. Using multilevel generalized linear models, we investigated the association of infant mortality with county urban-rural classification, considering county health system resources and measures of socioeconomic advantage, net of individual-level characteristics, and controlling for US region and county centroid. RESULTS: Infant mortality rates were highest in noncore (odds ratio [OR] = 1.32, 95% confidence interval [CI]: 1.26-1.39) and micropolitan counties (OR = 1.26, 95% CI: 1.20-1.32) when compared with large metropolitan fringe counties, controlling for geospatial measures. Inclusion of county health system characteristics did little to attenuate the greater odds of infant mortality in rural counties. Instead, a composite measure of county-level socioeconomic advantage was highly protective (adjusted OR = 0.84; 95% CI: 0.82-0.86) and eliminated any difference between the micropolitan and noncore counties and the large metropolitan fringe counties. CONCLUSIONS: Higher infant mortality rates in rural counties are best explained by their greater socioeconomic disadvantage than more-limited access to health care or the greater prevalence of mothers' individual health risks.

Peripartum Blood Transfusion Among Rural Women in the United States.

OBJECTIVE: To evaluate the peripartum transfusion rates for rural women compared with urban women in the United States. METHODS: In this population-based retrospective cohort study, geocoded birth records from 2014 to 2016 from the National Center for Health Statistics were used to examine the rural-urban differences in blood transfusion among nulliparous women delivering singleton, vertex pregnancies at term. We compared transfusion rates across the counties on a continuum from urban to rural. We generated a multivariable logistic regression model controlling for age, race, nativity, education, insurance, prenatal care, maternal health, gestational age, intrapartum care, mode of delivery, peripartum factors, and county of delivery. RESULTS: Among 3,346,816 births, the transfusion rates based on maternal county of residence increased as the counties became more rural: large metropolitan-center (1.9/1,000 live births); large metropolitan-fringe (2.4); medium metropolitan (2.6); small metropolitan (2.6); micropolitan (4.5); and noncore rural (5.3). Rural women living and delivering in a rural county had more transfusions (8.5/1,000 live births) than women in more urban counties (2.5/1,000). After adjusting for key covariates, the odds of transfusion were higher among women living in micropolitan (adjusted odds ratio [aOR] 2.25, 95% CI 2.09-2.43) and noncore rural (aOR 2.59, 95% CI 2.38-2.81) counties when compared with women living in large metropolitan counties. County of delivery had a higher association with transfusion than resident county. After adding delivery county to the regression model, the association of transfusion and living in a micropolitan (aOR 1.39, 95% CI 1.19-1.63) or noncore rural (aOR 1.32, 95% CI 1.12-1.55) county diminished. CONCLUSION: The odds of blood transfusion were higher for women in rural areas. The results indicate that the rurality of the county where the birth occurred was associated with more transfusion. This may reflect differences in maternity and blood banking services in rural hospitals and warrants further study to identify opportunities for intervention.