From paradox to disparity: trends in neonatal death in very low birth weight non-Hispanic black and white infants, 1989-2004

Racial disparities in the development of comorbid conditions after preterm birth: A narrative review

Despite recognition and attempts to reduce racial disparities in perinatal outcomes, Black infants are still disproportionately represented among those who are born preterm. Postnatal investigations of racial disparities in comorbidities and outcomes after preterm birth are increasing, although their results and interpretations are conflicting. In the present review, we 1.) identify important methodological limitations of that literature 2.) summarize the conflicting literature investigating racial disparities, specifically Black-white differences, in postnatal comorbidities and outcomes after preterm birth 3.) describe mechanisms by which racism operates to contextualize our understanding to inform future work to actively reduce disparities in preterm birth and subsequently, its complications.

Racial/Ethnic Disparities Among Extremely Preterm Infants in the United States From 2002 to 2016

IMPORTANCE

Racial/ethnic disparities in quality of care among extremely preterm infants are associated with adverse outcomes.

OBJECTIVE

To assess whether racial/ethnic disparities in major outcomes and key care practices were changing over time among extremely preterm infants.

DESIGN, SETTING, AND PARTICIPANTS

This observational cohort study used prospectively collected data from 25 US academic medical centers. Participants included 20 092 infants of 22 to 27 weeks' gestation with a birth weight of 401 to 1500 g born at centers participating in the National Institute of Child Health and Human Development Neonatal Research Network from 2002 to 2016. Of these infants, 9316 born from 2006 to 2014 were eligible for follow-up at 18 to 26 months' postmenstrual age (excluding 5871 infants born before 2006, 2594 infants born after 2014, and 2311 ineligible infants including 64 with birth weight >1000 g and 2247 infants with gestational age >26 6/7 weeks), of whom 745 (8.0%) did not have known follow-up outcomes at 18 to 26 months.

MAIN OUTCOMES AND MEASURES

Rates of mortality, major morbidities, and care practice use over time were evaluated using models adjusted for baseline characteristics, center, and birth year. Data analyses were conducted from 2018 to 2019.

RESULTS

In total, 20 092 infants with a mean (SD) gestational age of 25.1 (1.5) weeks met the inclusion criteria and were available for the primary outcome: 8331 (41.5%) black infants, 3701 (18.4%) Hispanic infants, and 8060 (40.1%) white infants. Hospital mortality decreased over time in all groups. The rate of improvement in hospital mortality over time did not differ among black and Hispanic infants compared with white infants (black infants went from 35% to 24%, Hispanic infants went from 32% to 27%, and white infants went from 30% to 22%; P = .59 for race × year interaction). The rates of late-onset sepsis among black infants (went from 37% to 24%) and Hispanic infants (went from 45% to 23%) were initially higher than for white infants (went from 36% to 25%) but decreased more rapidly and converged during the most recent years (P = .02 for race × year interaction). Changes in rates of other major morbidities did not differ by race/ethnicity. Death before follow-up decreased over time (from 2006 to 2014: black infants, 14%; Hispanic infants, 39%, white infants, 15%), but moderate-severe neurodevelopmental impairment increased over time in all racial/ethnic groups (increase from 2006 to 2014: black infants, 70%; Hispanic infants, 123%; white infants, 130%). Rates of antenatal corticosteroid exposure (black infants went from 72% to 90%, Hispanic infants went from 73% to 83%, and white infants went from 86% to 90%; P = .01 for race × year interaction) and of cesarean delivery (black infants went from 45% to 59%, Hispanic infants went from 49% to 59%, and white infants went from 62% to 63%; P = .03 for race × year interaction) were initially lower among black and Hispanic infants compared with white infants, but these differences decreased over time.

CONCLUSIONS AND RELEVANCE

Among extremely preterm infants, improvements in adjusted rates of mortality and most major morbidities did not differ by race/ethnicity, but rates of neurodevelopmental impairment increased in all groups. There were narrowing racial/ethnic disparities in important care practices, including the use of antenatal corticosteroids and cesarean delivery.

Racial and ethnic differences in preterm birth: A complex, multifactorial problem

Preterm birth remains the leading cause of morbidity and mortality among nonanomalous neonates, and is a major public health problem. Non-Hispanic black women have a 2-fold greater risk for preterm birth compared with non-Hispanic white race. The reasons for this disparity are poorly understood and cannot be explained solely by sociodemographic factors. Underlying factors including a complex interaction between maternal, paternal, and fetal genetics, epigenetics, the microbiome, and these sociodemographic risk factors likely underlies the differences between racial groups, but these relationships are currently poorly understood. This article reviews the epidemiology of disparities in preterm birth rates and adverse pregnancy outcomes and discuss possible explanations for the racial and ethnic differences, while examining potential solutions to this major public health problem.

Racial/Ethnic Disparities in Morbidity and Mortality for Preterm Neonates Admitted to a Tertiary Neonatal Intensive Care Unit

OBJECTIVE

The objective of this study was to assess whether in-hospital morbidity or mortality differed by race/ethnicity for preterm neonates admitted to the neonatal intensive care unit (NICU).

STUDY DESIGN

In a retrospective cohort study, preterm infants, < 37 weeks, were admitted to the NICU from 1994 to 2009. Exclusions included structural anomalies and aneuploidy. Primary outcome was in-hospital mortality (IHM). Secondary outcomes were respiratory distress syndrome (RDS), interventricular hemorrhage (IVH), necrotizing enterocolitis (NEC), and retinopathy of prematurity (ROP). Sub-analysis of very preterm (VPT) infants, < 28 weeks, was performed. Five racial/ethnic groups (REGs) were compared: White, Black, Hispanic, Asian, and Mixed. Associations were modeled by logistic regression. White neonates (WNs) were the referent group. Unadjusted and adjusted odds ratios and 95% confidence intervals for remaining REGs were reported. p value was significant at 5% for overall tests and at Bonferroni-corrected level < 0.0125 for between-race comparisons with WNs.

RESULTS

Four thousand nine hundred fifty-five preterm neonates were identified; 153 were excluded leaving 4802 for analysis. After controlling covariates that were chosen a priori, there was no difference across REGs for IHM (all between-race comparison p values > 0.0125). There was a significant difference in RDS among Black neonates (BNs) (aOR 0.57, 95% CI 0.45-0.73; p < 0.001) and Hispanic neonates (HNs) (aOR 0.67, 95% CI 0.50-0.89; p = 0.005) compared to WNs. The risk of ROP was significantly different across REGs with HNs having a 70% increase in ROP (aOR 1.70, 95% CI 1.15-2.49; p = 0.008) and Mixed neonates (MNs) experiencing a 55% reduction (aOR 0.45, 95% CI 0.29-0.68; p < 0.001) compared to WNs. There was no difference in IVH or NEC across REGs (all p values > 0.0125). In the VPT cohort sub-analysis, BNs experienced a significant 59% reduction in IHM compared to WNs (BNs aOR 0.41, 95% CI 0.22-0.73; p = 0.003). MNs experienced a 46% reduction in ROP compared to WNs (aOR 0.54, 95% CI 0.35-0.81; p = 0.004). There was no difference in RDS, IVH, or NEC in very preterm infants across REGs (all between comparison p values > 0.0125).

CONCLUSION

In preterm neonates, in-hospital mortality does not significantly differ across racial and ethnic groups. However, in very preterm infants, in-hospital mortality for Black neonates is improved. There are morbidity differences (RDS, ROP) seen among racial/ethnic groups.

The changing character of the Black-White infant mortality gap, 1983-2004

OBJECTIVES

We examined how changes in demographic, geographic, and childbearing risk factors were related to changes in the Black-White infant mortality rate (IMR) gap over 2 decades.

METHODS

Using 1983-2004 Vital Statistics, we applied inverse probability weighting methods to examine the relationship between risk factors and 3 outcomes: the overall IMR gap, its birth weight component, and its conditional (on birth weight) IMR component.

RESULTS

The unexplained IMR gap (the part not related to observed risk factors) was stable, changing from 5.0 to 5.3 deaths per 1000 live births. By contrast, the explained gap declined from 4.6 to 1.9. The decline in the explained gap was driven by the changing relationship between risk factors and IMR. Further analysis revealed that most of the unexplained gap occurred among infants weighing less than 1000 grams at birth, whereas most of the explained gap occurred among infants weighing more than 1000 grams.

CONCLUSIONS

The unexplained gap was stable over the last 2 decades, but the explained gap declined markedly. If the stability of the unexplained gap continues, even complete convergence of risk factors would reduce the Black-White IMR gap by only one quarter.

Increased risk of death among uninsured neonates

OBJECTIVE

To estimate the contribution of health insurance status to the risk of death among hospitalized neonates.

DATA SOURCES

Kids' Inpatient Databases (KID) for 2003, 2006, and 2009.

STUDY DESIGN

KID 2006 subpopulation of neonatal discharges was analyzed by weighted frequency distribution and multivariable logistic regression analyses for the outcome of death, adjusted for insurance status and other variables. Multivariable linear regression analyses were conducted for the outcomes mean adjusted length of stay and hospital charges. The death analysis was repeated with KID 2003 and 2009.

PRINCIPAL FINDINGS

Of 4,318,121 estimated discharges in 2006, 5.4 percent were uninsured. There were 17,892 deaths; 9.5 percent were uninsured. The largest risks of death were five clinical conditions with adjusted odds ratios (AOR) of 13.7-3.1. Lack of insurance had an AOR of 2.6 (95 percent CI: 2.4, 2.8), greater than many clinical conditions; AOR estimates in alternate models were 2.1-2.7. Compared with insureds, uninsureds were less likely to have been admitted in transfer, more likely to have died in rural hospitals and to have received fewer resources. Similar death outcome results were observed for 2003 and 2009.

CONCLUSIONS

Uninsured neonates had decreased care and increased risk of dying.

Smoking and respiratory conditions in pregnancy: associations with adverse pregnancy outcomes

OBJECTIVES

Acute and chronic respiratory conditions affect a large segment of pregnant women. The purpose of the current study was to examine the concomitant effects of respiratory conditions and smoking during pregnancy on gestational age, birth weight, fetal distress, infant mortality, premature rupture of membranes, placenta abruption, and mode of delivery.

METHODS

This study used data (n = 1,064,969) from the North Carolina linked birth/infant death files from 1999 to 2007. Logistic regression was used to compute odds ratios and 95% confidence intervals (CIs) in assessing risk of adverse pregnancy outcomes.

RESULTS

We found that women with respiratory conditions/smoking status were significantly more likely than nonsmokers with no respiratory conditions to have a low-birth-weight infant, an infant with fetal distress, and experience preterm birth and an infant's death. Adjusted odds ratios also revealed that smokers with respiratory conditions were 2.37 (95% CI 1.69-3.32) times more likely than women with no respiratory conditions/nonsmoking status to have placenta abruption and 2.20 (95% CI 1.85-2.61) times more likely to have premature rupture of membranes. Regardless of smoking status, women with respiratory conditions were less likely to have a vaginal delivery.

CONCLUSIONS

These findings underscore the need for clinical and public health programs to educate women, particularly those with respiratory diseases, of the immense array of adverse outcomes that may occur as a consequence of active maternal smoking during gestation. It is important for interventions to target mothers with respiratory conditions early on to ensure favorable birth outcomes.

Preconception mental health predicts pregnancy complications and adverse birth outcomes: a national population-based study

Pregnancy complications and poor birth outcomes can affect the survival and long-term health of children. The preconception period represents an opportunity to intervene and improve outcomes; however little is known about women's mental health prior to pregnancy as a predictor of such outcomes. We sought to determine if and to what extent women's preconception mental health status impacted subsequent pregnancy complications, non-live birth, and birth weight using a nationally representative, population-based sample. We used pooled 1996-2006 data from the nationally-representative Medical Expenditure Panel Survey (MEPS). Poor preconception mental health was defined as women's global mental health rating of "fair" or "poor" before conception. Logistic regression was used to assess the association between preconception mental health and pregnancy complications, non-live birth, and having a low birth weight baby within the follow up period. Poor preconception mental health was associated with increased odds of experiencing any pregnancy complication (AOR 1.40, 95% CI: 1.02-1.92), having a non-live birth (AOR 1.48, 95% CI: 0.96-2.27), and having a low birth weight baby (AOR 1.99, 95% CI: 1.00-3.98), all controlling for maternal age, race/ethnicity, marital status, education, health insurance status, income, and number of children in the household. Significant racial and ethnic disparities exist for pregnancy complications and non-live births, but not for low birth weight. Women's preconception mental health is a modifiable risk factor that stands to reduce the incidence of adverse pregnancy complications and birth outcomes.

Racial, ethnic, and socioeconomic disparities in the prevalence of cerebral palsy

OBJECTIVE

Racial and ethnic disparities in cerebral palsy have been documented, but the underlying mechanism is poorly understood. We determined whether low birth weight accounts for ethnic disparities in the prevalence of cerebral palsy and whether socioeconomic factors impact cerebral palsy within racial and ethnic groups.

METHODS

In a retrospective cohort of 6.2 million births in California between 1991 and 2001, we compared maternal and infant characteristics among 8397 infants with cerebral palsy who qualified for services from the California Department of Health Services and unaffected infants.

RESULTS

Overall, black infants were 29% more likely to have cerebral palsy than white infants (relative risk: 1.29 [95% confidence interval: 1.19-1.39]). However, black infants who were very low or moderately low birth weight were 21% to 29% less likely to have cerebral palsy than white infants of comparable birth weight. After we adjusted for birth weight, there was no difference in the risk of cerebral palsy between black and white infants. In multivariate analyses, women of all ethnicities who did not receive any prenatal care were twice as likely to have infants with cerebral palsy relative to women with an early onset of prenatal care. Maternal education was associated with cerebral palsy in a dose-response fashion among white and Hispanic women. Hispanic adolescent mothers (aged <18 years) had increased risk of having a child with cerebral palsy.

CONCLUSIONS

The increased risk of cerebral palsy among black infants is primarily related to their higher risk of low birth weight. Understanding how educational attainment and use of prenatal care impact the risk of cerebral palsy may inform new prevention strategies.