Distinct Populations of Sudden Unexpected Infant Death Based on Age

The effect of fertility treatment and socioeconomic status on neonatal and post-neonatal mortality in the United States

OBJECTIVE

To determine the association between fertility treatment, socioeconomic status (SES), and neonatal and post-neonatal mortality.

STUDY DESIGN

Retrospective cohort study of all births (19,350,344) and infant deaths from 2014-2018 in the United States. The exposure was mode of conception-spontaneous vs fertility treatment. The outcome was neonatal (<28d), and post-neonatal (28d-1y) mortality. Multivariable logistic models were stratified by SES.

RESULT

The fertility treatment group had statistically significantly higher odds of neonatal mortality (high SES OR 1.59; CI [1.5, 1.68], low SES OR 2.11; CI [1.79, 2.48]) and lower odds of post-neonatal mortality (high SES OR 0.87, CI [0.76, 0.996], low SES OR 0.6, CI [0.38, 0.95]). SES significantly modified the effect of ART/NIFT on neonatal and post-neonatal mortality.

CONCLUSIONS

Fertility treatment is associated with higher neonatal and lower post-neonatal mortality and SES modifies this effect. Socioeconomic policies and support for vulnerable families may help reduce rates of infant mortality.

Known pathogenic gene variants and new candidates detected in Sudden Unexpected Infant Death using Whole Genome Sequencing

Purpose

To gain insights into potential genetic factors contributing to the infant's vulnerability to Sudden Unexpected Infant Death (SUID).

Methods

Whole Genome Sequencing (WGS) was performed on 145 infants that succumbed to SUID, and 576 healthy adults. Variants were filtered by gnomAD allele frequencies and predictions of functional consequences.

Results

Variants of interest were identified in 86 genes, 63.4% of our cohort. Seventy-one of these have been previously associated with SIDS/SUID/SUDP. Forty-three can be characterized as cardiac genes and are related to cardiomyopathies, arrhythmias, and other conditions. Variants in 22 genes were associated with neurologic functions. Variants were also found in 13 genes reported to be pathogenic for various systemic disorders. Variants in eight genes are implicated in the response to hypoxia and the regulation of reactive oxygen species (ROS) and have not been previously described in SIDS/SUID/SUDP. Seventy-two infants met the triple risk hypothesis criteria (Figure 1).

Conclusion

Our study confirms and further expands the list of genetic variants associated with SUID. The abundance of genes associated with heart disease and the discovery of variants associated with the redox metabolism have important mechanistic implications for the pathophysiology of SUID.

Associations Between Breastfeeding and Post-perinatal Infant Deaths in the U.S

INTRODUCTION

Initiation of breastfeeding has been associated with reduced post-perinatal infant mortality. Although most states have initiatives to protect, promote, and support breastfeeding, no analysis of the association between breastfeeding and infant mortality has been conducted at the state and regional levels. To understand the associations between breastfeeding and post-perinatal infant mortality, the initiation of breastfeeding with post-perinatal infant mortality was analyzed by geographic region and individual states within each region.

METHODS

This study was a prospective cohort analysis linking U.S. national birth and post-perinatal infant death data for nearly 10 million infants born in 2016-2018, who were then followed for one year after birth and analyzed in 2021-2022.

RESULTS

A total of 9,711,567 live births and 20,632 post-perinatal infant deaths from 48 states and the District of Columbia were included in the analysis. The overall AOR and 95% CIs for breastfeeding initiation with post-perinatal infant mortality was 0.67 (0.65, 0.69, p<0.0001) for days 7-364. All seven U.S. geographic regions had significant reductions in postperinatal infant deaths associated with breastfeeding initiation; Mid-Atlantic and Northeast regions had the largest reductions with AOR of 0.56 (95% CI=0.51, 0.61, p<0.001 and 0.50, 0.63, p<0.001, respectively), whereas the Southeast had the smallest reduction with AOR of 0.79 (95% CI=0.75, 0.84, p<0.001). Statistically significant results were noted for 35 individual states for reduction in total post-perinatal infant deaths.

CONCLUSIONS

Although regional and state variation in the magnitude of the association between breastfeeding and infant mortality exists, the consistency of reduced risk, together with existing literature, suggests that breastfeeding promotion and support may be a strategy to reduce infant mortality in the U.S.

Maternal, infant, and environmental risk factors for sudden unexpected infant deaths: results from a large, administrative cohort

OBJECTIVES

Many studies of sudden unexpected infant death (SUID) have focused on individual domains of risk factors (maternal, infant, and environmental), resulting in limited capture of this multifactorial outcome. The objective of this study was to examine the geographic distribution of SUID in San Diego County, and assess maternal, infant, and environmental risk factors from a large, administrative research platform.

STUDY DESIGN

Births in California between 2005 and 2017 were linked to hospital discharge summaries and death files. From this retrospective birth cohort, cases of SUID were identified from infant death files in San Diego County. We estimated adjusted hazard ratios (aHRs) for infant, maternal, and environmental factors and SUID in multivariable Cox regression analysis. Models were adjusted for maternal sociodemographic characteristics and prenatal nicotine exposure.

RESULTS

There were 211 (44/100,000 live births; absolute risk 0.04%) infants with a SUID among 484,905 live births. There was heterogeneity in geographic distribution of cases. Multiparity (0.05%; aHR 1.4, 95% confidence interval (CI) 1.1, 1.9), maternal depression (0.11%; aHR 1.8, 95% CI 1.0, 3.4), substance-related diagnoses (0.27%; aHR 2.3, 95% CI 1.3, 3.8), cannabis-related diagnosis (0.35%; aHR 2.7, 95% CI 1.5, 5.0), prenatal nicotine use (0.23%; aHR 2.5, 95% CI 1.5, 4.2), preexisting hypertension (0.11%; aHR 2.3, 95% CI 1.2, 4.3), preterm delivery (0.09%; aHR 2.1, 95% CI 1.5, 3.0), infant with a major malformation (0.09%; aHR 2.0, 95% CI 1.1, 3.6), respiratory distress syndrome (0.12%; aHR 2.6, 95% CI 1.5, 4.6), and select environmental factors were all associated with SUID.

CONCLUSIONS

Multiple risk factors were confirmed and expanded upon, and the geographic distribution for SUID in San Diego County was identified. Through this approach, prevention efforts can be targeted to geographies that would benefit the most.

Sudden unexpected infant death risk profiles in the first month of life

BACKGROUND

Limited improvement in current SUID rates requires further identification of its characteristics, including age-specific risk patterns.

OBJECTIVE

Compare SUID risk factors in the first week versus the remainder in the first month of life.

DESIGN/METHODS

We compared maternal and infant data from New Jersey databases for SUID from 2000 to 2015 in infants ≥ 34 weeks GA in the two groups.

RESULTS

In the period studied, 123 died in the first 27 days, 24 before seven. Deaths in the first week had a higher percentage of mothers with post-High School education (OR 3.50, CI: 1.38-8.87) and a primary Cesarean section delivery (OR 4.0, CI: 1.39-11.49), and a smaller percentage with inadequate prenatal care (OR 0.36, CI: 0.14, 0.94). A smaller percentage of first-week deaths had mothers who smoked during pregnancy or identified as Black, non-Hispanic, but these findings did not reach significance (p < .08 and p < .09, respectively).

CONCLUSIONS

SUID in the first week and the first month of life is rare. However, despite a limited sample size, data suggest that even within the first month of life, there are differences in risk patterns for SUID based on age at death. Age-specific profiles may lead to new hypotheses regarding causality and more refined risk-reduction guidelines and warrant further study.

Challenges and Opportunities of Using a National Database to Evaluate Racial/Ethnic Disparities and Breastfeeding Effects on Sudden Unexpected Infant Death

Background: Sudden unexpected infant death (SUID) rates remain higher in American Indian/Alaska Native (AI/AN) and non-Hispanic Black (NHB) infants than other demographic groups. Racial disparities are also evident in breastfeeding, which is associated with reduced risk of SUID. Objective: To assess the relationship between racial/ethnic disparities in SUID and breastfeeding beyond the newborn period using U.S. nationally reported public databases. Methods: Data were extracted from Centers for Disease Control and Prevention Wide-ranging Online Data for Epidemiologic Research (WONDER) and the National Immunization Surveys (NISs) 2009-2017. WONDER data were restricted to full-term infants and sorted by death year, race/ethnicity, and other characteristics. NIS breastfeeding data included ever breastfed, breastfed at 6 months, and exclusive breastfeeding at 3 and 6 months. Breastfeeding rates and mortality data were aggregated based on race/ethnicity, and mortality rates were analyzed by weighted (number of births) multivariable linear regression. Results: SUID rates were highest among NHB and AI/AN infants who also had the lowest breastfeeding rates. When breastfeeding and race/ethnicity were included in the analyses, race/ethnicity confounded the relationship between breastfeeding and SUID. When race was excluded, ever breastfeeding and any breastfeeding at 6 months were associated with significantly decreased SUID rates. Conclusion: Race/ethnicity confounded the relationship between breastfeeding and SUID. Analysis was limited because individual SUID rates were available for maternal/birth characteristics but not for breastfeeding. Our study showed a need for adding additional data points to other national databases to better understand the role that breastfeeding plays in the racial/ethnic disparities in SUID.

Differences in Mortality Among Infants With Neonatal Opioid Withdrawal Syndrome

INTRODUCTION

Prior studies are mixed regarding whether infants diagnosed with neonatal opioid withdrawal syndrome have a higher risk of mortality than other infants. However, these studies have not accounted for whether mothers of infants with neonatal opioid withdrawal syndrome received medication for opioid use disorder in pregnancy.

METHODS

Linked data from 2016‒2018 North Carolina birth certificates, maternal and infant Medicaid claims, and infant death certificates were analyzed in summer 2021 to compare mortality and causes of mortality before age 1 year among infants diagnosed with neonatal opioid withdrawal syndrome whose mothers did and did not have claims for medication for opioid use disorder in pregnancy (N=4,480).

RESULTS

Compared with mothers with medication for opioid use disorder claims in pregnancy (45.5%), mothers without medication for opioid use disorder claims (55.5%) were younger, more likely to be Black non-Hispanic, less likely to have paternity established, and more likely to have no prenatal care. The proportion (1.3%, n=31 vs 1.0%, n=21) and rate (3.5 vs 2.9 deaths per 100,000 infant days) of mortality was higher among infants of mothers without medication for opioid use disorder claims than infants of mothers with medication for opioid use disorder claims. Sudden unexpected infant death syndrome was the primary cause of death for infants of mothers with (90.5%) and without (58.1%) medication for opioid use disorder claims.

CONCLUSIONS

Results highlight the importance of assessing for potential differences in outcomes according to whether infants with neonatal opioid withdrawal syndrome were exposed to medication for opioid use disorder. Efforts to ensure equitable access to medication for opioid use disorder and other support services in pregnancy are needed to promote healthy maternal and infant outcomes.

Evidence Base for 2022 Updated Recommendations for a Safe Infant Sleeping Environment to Reduce the Risk of Sleep-Related Infant Deaths

Every year in the United States, approximately 3500 infants die of sleep-related infant deaths, including sudden infant death syndrome (SIDS) (International Statistical Classification of Diseases and Related Health Problems 10th Revision [ICD-10] R95), ill-defined deaths (ICD-10 R99), and accidental suffocation and strangulation in bed (ICD-10 W75). After a substantial decline in sleep-related deaths in the 1990s, the overall death rate attributable to sleep-related infant deaths have remained stagnant since 2000, and disparities persist. The triple risk model proposes that SIDS occurs when an infant with intrinsic vulnerability (often manifested by impaired arousal, cardiorespiratory, and/or autonomic responses) undergoes an exogenous trigger event (eg, exposure to an unsafe sleeping environment) during a critical developmental period. The American Academy of Pediatrics recommends a safe sleep environment to reduce the risk of all sleep-related deaths. This includes supine positioning; use of a firm, noninclined sleep surface; room sharing without bed sharing; and avoidance of soft bedding and overheating. Additional recommendations for SIDS risk reduction include human milk feeding; avoidance of exposure to nicotine, alcohol, marijuana, opioids, and illicit drugs; routine immunization; and use of a pacifier. New recommendations are presented regarding noninclined sleep surfaces, short-term emergency sleep locations, use of cardboard boxes as a sleep location, bed sharing, substance use, home cardiorespiratory monitors, and tummy time. In addition, additional information to assist parents, physicians, and nonphysician clinicians in assessing the risk of specific bed-sharing situations is included. The recommendations and strength of evidence for each recommendation are published in the accompanying policy statement, which is included in this issue.

The Role of Breastfeeding in Racial and Ethnic Disparities in Sudden Unexpected Infant Death: A Population-Based Study of 13 Million Infants in the United States

Sudden unexpected infant death (SUID) disproportionately affects non-Hispanic Black (NHB) and American Indian/Alaskan Native infants, who have lower rates of breastfeeding than other groups. Using 13,077,880 live-birth certificates and 11,942 linked SUID death certificates from 2015 through 2018, we calculated odds ratios and adjusted risk differences of SUID in infants who were not breastfed across 5 racial/ethnic strata in the United States. We analyzed mediation by not breastfeeding in the race/ethnicity-SUID association. The overall SUID rate was 0.91 per 1,000 live births. NHB and American Indian/Alaskan Native infants had the highest disparity in SUID relative to non-Hispanic White infants. Overall, not breastfeeding was associated with SUID (adjusted odds ratio (aOR), 1.14; 95% confidence interval (CI): 1.10, 1.19), and the adjusted risk difference was 0.12 per 1,000 live births. The aOR of not breastfeeding for SUID was 1.07 (95% CI: 1.00, 1.14) in NHB infants and 1.29 (95% CI: 1.14, 1.46) in Hispanic infants. Breastfeeding minimally explained the higher SUID risk in NHB infants (2.3% mediated) and the lower risk in Hispanic infants (2.1% mediated) relative to non-Hispanic White infants. Competing risks likely explain the lower aOR seen in NHB infants of not breastfeeding on SUID, suggesting that social or structural determinants must be addressed to reduce racial disparities in SUID.

A proof-of-concept study to construct Bayesian network decision models for supporting the categorization of sudden unexpected infant death

Sudden infant death syndrome (SIDS) remains a leading cause of infant death in high-income countries. Supporting models for categorization of sudden unexpected infant death into SIDS/non-SIDS could reduce mortality. Therefore, we aimed to develop such a tool utilizing forensic data, but the reduced number of SIDS cases renders this task inherently difficult. To overcome this, we constructed Bayesian network models according to diagnoses performed by expert pathologists and created conditional probability tables in a proof-of-concept study. In the diagnostic support model, the data of 64 sudden unexpected infant death cases was employed as the training dataset, and 16 known-risk factors, including age at death and co-sleeping, were added. In the validation study, which included 8 new cases, the models reproduced experts’ diagnoses in 4 or 5 of the 6 SIDS cases. Next, to confirm the effectiveness of this approach for onset prediction, the data from 41 SIDS cases was employed. The model predicted that the risk of SIDS in 0- to 2-month-old infants exposed to passive smoking and co-sleeping is eightfold higher than that in the general infant population, which is comparable with previously published findings. The Bayesian approach could be a promising tool for constructing SIDS prevention models.

A "Good Death" for Children with Cardiac Disease

Children with heart disease often experience symptoms and medically intense end-of-life care. Our study explored bereaved parents' perceptions of a "good death" via a mail survey to 128 parents of children with heart disease who died in two centers. Parental perceptions of end-of-life circumstances were assessed by closed-ended questions including level of agreement with the question: "would you say your child experienced a good death?" and open-ended comments were contributed. Medical therapies at end-of-life and mode of death were retrieved through chart review. Of 50 responding parents, 44 (response rate: 34%) responded to the "good death" question; 16 (36%) agreed strongly, 15 (34%) agreed somewhat, and 30% disagreed (somewhat: 7, 16%; strongly: 6, 14%). Half the children were on mechanical support and 84% intubated at death. Of children with cardiopulmonary resuscitation (CPR) at end-of-life, 71% of parents disagreed with the "good death" question compared with 22% of parents whose child died following discontinuation of life-sustaining therapy or comfort measures (OR 9.1, 95% CI 1.3, 48.9, p < 0.01). Parent-reported circumstances associated with disagreement with the "good death" question included cure-oriented goals-of-care (OR 16.6, 95% CI 3.0, 87.8, p < 0.001), lack of advance care planning (ACP) (OR 12.4 95% CI 2.1, 65.3 p < 0.002), surprise regarding timing of death (OR 11.7, 95% CI 2.6, 53.4 p < 0.002), and experience of pain (OR 42.1, 95% CI 2.3, 773.7 p < 0.02). Despite high medical intensity, many bereaved parents of children with cardiac disease agree a "good death" was experienced. A "good death" was associated with greater preparedness, ACP, non-cure-oriented goals-of-care, pain control, and CPR avoidance.

Breastfeeding and post-perinatal infant deaths in the United States, A national prospective cohort analysis

Background

Reducing infant mortality is a major public health goal. The potential impact of breastfeeding on infant deaths is not well studied in the United States (US).

Methods

We analyzed linked birth-death certificates for 3,230,500 US births that occurred in 2017, including 6,969 post-perinatal deaths from 7-364 days of age as the primary outcome, further specified as late-neonatal (7-27 days) or post-neonatal (28-364 days) deaths. The primary exposure was 'ever breastfed' obtained from birth certificates. Multiple logistic regression examined associations of ever breastfeeding with post-perinatal deaths and specific causes of deaths, controlling for maternal and infant factors.

Findings

We observed an adjusted reduced odds ratio (AOR)= 0·74 with 95% confidence intervals (CI)=0·70-0·79 for the association of breastfeeding initiation with overall infant deaths (7-364 days), AOR=0·60 (0·54-0·67) for late-neonatal deaths, and AOR=0·81 (0·76-0·87) for post-neonatal deaths. In race/ethnicity-stratified analysis, significant associations of breastfeeding initiation with reduced odds of overall infant deaths were observed for Hispanics [AOR=0·64 (0·55-0·74)], non-Hispanic Whites [AOR=0·75 (0·69-0·81)], non-Hispanic Blacks [AOR=0·83 (0·75-0·91)], and non-Hispanic Asians [AOR=0·51 (0·36-0·72)]. Across racial/ethnic groups, effect sizes for late-neonatal deaths were consistently larger than those for post-neonatal deaths. Significant effects of breastfeeding initiation were observed for deaths due to infection [AOR=0·81(0·69-0·94)], Sudden Unexpected Infant Death [AOR=0·85 (0·78-0·92)], and necrotizing enterocolitis [AOR=0·67 (0·49-0·90)].

Interpretation

Breastfeeding initiation is significantly associated with reduced odds of post-perinatal infant deaths in multiple racial and ethnic groups within the US population. These findings support efforts to improve breastfeeding in infant mortality reduction initiatives.

Sudden Unexpected Infant Death: Keeping the Newborn Safe in Hospital and at Home

Sudden unexpected infant death is a leading cause of death in infancy. Both safe sleep practices and breastfeeding can help decrease the risk, although the current practice of educating parents about the recommendations has not resulted in universal adherence. Prenatal counseling provides opportunities to discuss recommendations as well as troubleshoot common barriers to breastfeeding and safe infant sleep with goals to gradually change attitudes, address social norms, and prepare new parents. A conversational, motivational approach to discussions about the importance of safe sleep and continued breastfeeding, with explanations as to the reasoning behind these recommendations, can help parents incorporate optimal practices into their lifestyles in a way that is sustainable for adherence.

Machine Learning Approaches to Determine Feature Importance for Predicting Infant Autopsy Outcome

INTRODUCTION

Sudden unexpected death in infancy (SUDI) represents the commonest presentation of postneonatal death. We explored whether machine learning could be used to derive data driven insights for prediction of infant autopsy outcome.

METHODS

A paediatric autopsy database containing >7,000 cases, with >300 variables, was analysed by examination stage and autopsy outcome classified as 'explained (medical cause of death identified)' or 'unexplained'. Decision tree, random forest, and gradient boosting models were iteratively trained and evaluated.

RESULTS

Data from 3,100 infant and young child (<2 years) autopsies were included. Naïve decision tree using external examination data had performance of 68% for predicting an explained death. Core data items were identified using model feature importance. The most effective model was XG Boost, with overall predictive performance of 80%, demonstrating age at death, and cardiovascular and respiratory histological findings as the most important variables associated with determining medical cause of death.

CONCLUSION

This study demonstrates feasibility of using machine-learning to evaluate component importance of complex medical procedures (paediatric autopsy) and highlights value of collecting routine clinical data according to defined standards. This approach can be applied to a range of clinical and operational healthcare scenarios.

Infant Mortality Associated With Prenatal Opioid Exposure

IMPORTANCE

Knowledge of health outcomes among opioid-exposed infants is limited, particularly for those not diagnosed with neonatal opioid withdrawal syndrome (NOWS).

OBJECTIVES

To describe infant mortality among opioid-exposed infants and identify how mortality risk differs in opioid-exposed infants with and without a diagnosis of NOWS compared with infants without opioid exposure.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study of maternal-infant dyads was conducted, linking health care claims with vital records for births from January 1, 2010, to December 31, 2014, with follow-up of infants until age 1 year (through 2015). Maternal-infant dyads were included if the infant was born in Texas at 22 to 43 weeks' gestational age to a woman aged 15 to 44 years insured by Texas Medicaid. Data analysis was performed from May 2019 to October 2020.

EXPOSURE

The primary exposure was prenatal opioid exposure, with infants stratified by the presence or absence of a diagnosis of NOWS during the birth hospitalization.

MAIN OUTCOMES AND MEASURES

Risk of infant mortality (death at age <365 days) was examined using Kaplan-Meier and log-rank tests. A series of logistic regression models was estimated to determine associations between prenatal opioid exposure and mortality, adjusting for maternal and neonatal characteristics and clustering infants at the maternal level to account for statistical dependence owing to multiple births during the study period.

RESULTS

Among 1 129 032 maternal-infant dyads, 7207 had prenatal opioid exposure, including 4238 diagnosed with NOWS (mean [SD] birth weight, 2851 [624] g) and 2969 not diagnosed with NOWS (mean [SD] birth weight, 2971 [639] g). Infant mortality was 20 per 1000 live births for opioid-exposed infants not diagnosed with NOWS, 11 per 1000 live births for infants with NOWS, and 6 per 1000 live births in the reference group (P < .001). After adjusting for maternal and neonatal characteristics, mortality in infants with a NOWS diagnosis was not significantly different from the reference population (odds ratio, 0.82; 95% CI, 0.58-1.14). In contrast, the odds of mortality in opioid-exposed infants not diagnosed with NOWS was 72% greater than the reference population (odds ratio, 1.72; 95% CI, 1.25-2.37).

CONCLUSIONS AND RELEVANCE

In this study, opioid-exposed infants appeared to be at increased risk of mortality, and the treatments and supports provided to those diagnosed with NOWS may be protective. Interventions to support opioid-exposed maternal-infant dyads are warranted, regardless of the perceived severity of neonatal opioid withdrawal.

Differences in Postmortem Investigation Following Perinatal Death

OBJECTIVE

 The study aimed to describe the postmortem investigation patterns for perinatal deaths and compare the degree of investigation between stillbirths and early neonatal deaths.

STUDY DESIGN

 We conducted a single-center retrospective review of all perinatal deaths from 2011 to 2017. Perinatal death was defined as intrauterine fetal death at ≥20 weeks' gestation, plus neonatal deaths within the first 7 days of life. Rates of postmortem investigation were compared.

RESULTS

 There were 97 perinatal deaths, with 54 stillbirths (56%) and 43 neonatal deaths (44%). Stillbirths were significantly more likely to receive autopsy (p = 0.013) and postmortem genetic testing (p = 0.0004) when compared with neonatal deaths. Maternal testing was also more likely in stillbirths than neonatal deaths. A total of 32 deaths (33%) had no postmortem evaluation beyond placental pathology.

CONCLUSION

 Investigation following perinatal death is more likely in stillbirths than neonatal deaths. Methods to improve postmortem investigation following perinatal death are needed, particularly for neonatal deaths.

KEY POINTS

· Investigation into perinatal death is recommended.. · Rates of investigation remain low.. · Neonatal deaths with less investigation than stillbirths..

Impact of high-risk fertility behaviours on underfive mortality in Asia and Africa: evidence from Demographic and Health Surveys

Background

Maternal age < 18 or > 34 years, short inter-pregnancy birth interval, and higher birth order are considered to be high-risk fertility behaviours (HRFB). Underfive mortality being disproportionately concentrated in Asia and Africa, this study analyses the association between HRFB and underfive mortality in selected Asian and African countries.

Methods

This study used Integrated Public Microdata Series-Demographic and Health Surveys (IPUMS-DHS) data from 32 countries in sub-Saharan Africa, Middle East, North Africa and South Asia from 1986 to 2017 (N = 1,467,728). Previous evidence hints at four markers of HRFB: women’s age at birth of index child < 18 or > 34 years, preceding birth interval < 24 months and child’s birth order > 3. Using logistic regression, we analysed change in the odds of underfive mortality as a result of i) exposure to HRFB individually, ii) exposure to any single HRFB risk factor, iii) exposure to multiple HRFB risk factors, and iv) exposure to specific combinations of HRFB risk factors.

Results

Mother’s age at birth of index child < 18 years and preceding birth interval (PBI) < 24 months were significant risk factors of underfive mortality, while a child’s birth order > 3 was a protective factor. Presence of any single HRFB was associated with 7% higher risk of underfive mortality (OR 1.07; 95% CI 1.04–1.09). Presence of multiple HRFBs was associated with 39% higher risk of underfive mortality (OR 1.39; 95% CI 1.36–1.43). Some specific combinations of HRFB such as maternal age < 18 years and preceding birth interval < 24 month significantly increased the odds of underfive mortality (OR 2.07; 95% CI 1.88–2.28).

Conclusion

Maternal age < 18 years and short preceding birth interval significantly increase the risk of underfive mortality. This highlights the need for an effective legislation to curb child marriages and increased public investment in reproductive healthcare with a focus on higher contraceptive use for optimal birth spacing.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-03780-y.

Sudden Unexpected Postnatal Collapse Resulting in Newborn Death in the United States

BACKGROUND

The sudden collapse of an apparently healthy newborn, or sudden unexpected postnatal collapse (SUPC) is fatal in about half of cases. Epidemiological characteristics of sudden unexpected infant death (SUID) in the first week of life differ from those in the postperinatal age group (7-365 days).

AIM

To describe the characteristics of SUPC resulting in neonatal death.

METHODS

We analyzed the Centers for Disease Control and Prevention Birth Cohort Linked Birth/Infant Death Data Set (2003-2013: 41,125,233 births and 37,624 SUIDs). SUPC was defined as infants born ≥35 weeks gestational age, with a 5-minute Apgar score of ≥7, who died suddenly and unexpectedly in the first week of life.

RESULTS

Of the 37,624 deaths categorized as SUID during the study period, 616 met the SUPC criteria (1.5/100,000 live births). Eleven percent occurred on the first day of life and nearly three quarters occurred during postnatal days 3-6. SUPC deaths differed statistically from SUID deaths occurring 7-364 days of age, in particular for sex, marital status, and live birth order.

IMPLICATIONS

These data support the need for adequate nurse staffing during the immediate recovery period and for the entire postpartum stay as well as nurse rounding for new mothers in the hospital setting.

Peptides, Breathing, and Sudden Infant Death Syndrome

Shi et al. recently identified a brainstem peptidergic circuit in mice that is activated at birth and stabilizes breathing during the transition from the intra-utero environment to air breathing. This network remains important for maintaining stable breathing and respiratory homeostasis throughout development, and deficiencies in this network may be linked to sudden infant death syndrome (SIDS).

Altitude and risk of sudden unexpected infant death in the United States

The effect of altitude on the risk of sudden infant death syndrome (SIDS) has been reported previously, but with conflicting findings. We aimed to examine whether the risk of sudden unexpected infant death (SUID) varies with altitude in the United States. Data from the Centers for Disease Control and Prevention (CDC)'s Cohort Linked Birth/Infant Death Data Set for births between 2005 and 2010 were examined. County of birth was used to estimate altitude. Logistic regression and Generalized Additive Model (GAM) were used, adjusting for year, mother's race, Hispanic origin, marital status, age, education and smoking, father's age and race, number of prenatal visits, plurality, live birth order, and infant's sex, birthweight and gestation. There were 25,305,778 live births over the 6-year study period. The total number of deaths from SUID in this period were 23,673 (rate = 0.94/1000 live births). In the logistic regression model there was a small, but statistically significant, increased risk of SUID associated with birth at > 8000 feet compared with < 6000 feet (aOR = 1.93; 95% CI 1.00-3.71). The GAM showed a similar increased risk over 8000 feet, but this was not statistically significant. Only 9245 (0.037%) of mothers gave birth at > 8000 feet during the study period and 10 deaths (0.042%) were attributed to SUID. The number of SUID deaths at this altitude in the United States is very small (10 deaths in 6 years).

Factors associated with age of death in sudden unexpected infant death

Aim

This study aimed to systematically analyse the pregnancy, birth and demographic‐related factors associated with age of death in sudden unexpected infant death (SUID).

Methods

Data were analysed from the Centers for Disease Control and Prevention's Cohort Linked Birth/Infant Death data set (2011‐2013; 11 737 930 live births). SUID was defined as deaths from sudden infant death syndrome, ill‐defined causes, or accidental suffocation and strangulation in bed. There were 9668 SUID cases (7‐364 days; gestation >28 weeks; 0.82/1000 live births). The odds of death at different ages were compared to determine which variables significantly affect the SUID age of death.

Results

Forty‐three features indicated a significant change in age of death with two main patterns: (a) younger chronologic age at death was associated with maternal smoking and factors associated with lower socio‐economic status, and (b) older age was associated with low birthweight, prematurity and admission to the neonatal intensive care unit. However, when age was corrected for gestation, these factors were associated with younger age.

Conclusion

Factors that varied with age of death are well‐documented risk factors for SUID. The majority of these risk factors were associated with younger age at death after allowing for gestational age at birth.

The multiagency approach to Sudden Unexpected Infant Deaths (SUID): eleven years' experience in the Tuscany Region

Background

The Sudden Unexpected Infant Death Syndrome (SUID) is one of the leading causes of mortality in the first year of life. The aim of this work was the retrospective evaluation of the incidence of SUID and the effectiveness of the multiagency approach to this phenomenon in the Tuscany Region.

Methods

Data were obtained from the regional registry of SUID cases in the period 2009–2019. The registry contains both sudden unexpected deaths in the first week of life (Sudden Unexpected Early Neonatal Deaths - SUEND), and those occurring after the first week up to 1 year of age (SUID).

Results

In this timeframe a total of 73 sudden unexpected deaths occurred in our region; 32 were Unexplained (i.e. Sudden Infant Death Syndrome - SIDS), 24 Explained, 10 Undetermined, and 7 SUEND. Autopsies were performed in 91% of cases, and in 95% of these by three groups of selected pathologists according to our protocol.

We found a low incidence of SUID (0.21 ‰), and SIDS deaths accounted for 0.1‰ of live births (48% of cases) with a high prevalence of infants of non-Italian ethnicity (38% of cases). Bereaved families were able to receive psychological support from mental health professionals and have contact with the family association, Seeds for SIDS. Audits were organized when post-mortem examinations were not carried out or carried out incorrectly in procedural terms, and when the diagnosis was particularly uncertain.

Conclusions

This paper first provides data on SUID mortality based on complete post-mortems in an Italian region. According to these findings we can state that our approach is effective both in terms of correctly performed autopsies and support for bereaved families. Future efforts are necessary to further reduce the incidence of SUID especially among non- Italian infants. An improvement action is also recommended for ensuring a more accurate and consistent picture of the circumstances of death.

The final approval of the National Protocol for the management of SUID cases is therefore strongly advocated in order to improve surveillance in this specific field and abolish disparities among the Italian regions.

Geographic Variation in Sudden Unexpected Infant Death in the United States

OBJECTIVES

To assess the geographic variation of sudden unexpected infant death (SUID) and test if variation in geographic factors, such as state, latitude, and longitude, play a role in SUID risk across the US.

STUDY DESIGN

We analyzed the Centers for Disease Control and Prevention's Cohort Linked Birth/Infant Death dataset (2005-2010; 22 882 SUID cases, 25 305 837 live births, rate 0.90/1000). SUID was defined as infant deaths (ages 7-364 days) that included sudden infant death syndrome, ill-defined and unknown cause of mortality, and accidental suffocation and strangulation in bed. SUID geographic variation was analyzed using 2 statistical models, logistic regression and generalized additive model (GAM).

RESULTS

Both models produced similar results. Without adjustment, there was marked geographic variation in SUID rates, but the variation decreased after adjusting for covariates including known risk factors for SUID. After adjustment, nine states demonstrated significantly higher or lower SUID mortality than the national average. Geographic contribution to SUID risk in terms of latitude and longitude were also attenuated after adjustment for covariates.

CONCLUSION

Understanding why some states have lower SUID rates may enhance SUID prevention strategies.

Supporting African American Mothers during Nurse Home Visits in Adopting Safe Sleep Practices

BACKGROUND

Nurses providing home visits were concerned that some mothers were not routinely using safe sleep practices for their newborns and infants.

PURPOSE

The purpose of this study was to listen to how home visit nurses offer education to their African American clients about the safe to sleep guidelines during the prenatal and postpartum periods and discuss ways nurses could support mothers to be more successful in using safe sleep practices.

STUDY DESIGN AND METHODS

A focus group was conducted with home visit nurses who partner with pregnant mothers and follow them through the first 2 years of their child's life. We asked the nurses to discuss how they offer information and education to their African American clients about safe sleep practices and what could be done to support adoption of the guidelines. A qualitative narrative approach was used for data analysis.

RESULTS

Seventeen home visit nurses participated in the focus group. We identified two overall themes with eight subthemes. The first theme focused on nurses' perceptions about challenges some mothers have in following the recommendations. The second theme included nurses' perspectives on how to better promote the safe sleep message and educating mothers within their cultural context.

CLINICAL IMPLICATIONS

Expectant and new mothers need advice and knowledge about the Safe to Sleep guidelines that provide ways to decrease risk of infant death. Nurses must be aware of their clients' culture and beliefs so they can offer support and information on infant safety within that context.