Extreme prematurity: Risk and resiliency

Longstanding Auditory Sensory and Semantic Differences in Preterm Born Children

More than 10% of births are preterm, and the long-term consequences on sensory and semantic processing of non-linguistic information remain poorly understood. 17 very preterm-born children (born at < 33 weeks gestational age) and 15 full-term controls were tested at 10 years old with an auditory object recognition task, while 64-channel auditory evoked potentials (AEPs) were recorded. Sounds consisted of living (animal and human vocalizations) and manmade objects (e.g. household objects, instruments, and tools). Despite similar recognition behavior, AEPs strikingly differed between full-term and preterm children. Starting at 50ms post-stimulus onset, AEPs from preterm children differed topographically from their full-term counterparts. Over the 108-224ms post-stimulus period, full-term children showed stronger AEPs in response to living objects, whereas preterm born children showed the reverse pattern; i.e. stronger AEPs in response to manmade objects. Differential brain activity between semantic categories could reliably classify children according to their preterm status. Moreover, this opposing pattern of differential responses to semantic categories of sounds was also observed in source estimations within a network of occipital, temporal and frontal regions. This study highlights how early life experience in terms of preterm birth shapes sensory and object processing later on in life.

Neonatal inflammation and its association with asthma and obesity in late childhood among individuals born extremely preterm

BACKGROUND

Asthma and obesity are frequent outcomes among individuals born extremely preterm and are associated with decreased lifespan. Neonatal inflammation is associated with chronic neurodevelopmental disorders; however, it is less studied in association with other later childhood chronic disorders in this population.

METHODS

Fourteen hospitals in 5 U.S. states enrolled 1506 infants born before 28 weeks of gestation in the Extremely Low Gestational Age Newborn cohort in 2004-2014. Neonatal blood spots were collected on postnatal days 1, 7, 14, 21, and 28, and used to measure 14 inflammation-related proteins. Associations were evaluated between high (top quartile) levels of proteins and two chronic health disorders at ages 10 and 15 years: physician-diagnosed asthma and obesity (body mass index ≥95th percentile).

RESULTS

Few associations were found between high levels of 14 inflammation-related proteins, either on a single day or on multiple days, and either asthma or obesity. Similarly, few associations were found in analyses stratified by sex or presence/absence of prenatal inflammation.

CONCLUSIONS

In extremely preterm newborns, systemic elevations of inflammation-related proteins during the neonatal period were not associated with childhood asthma and obesity outcomes at 10 or 15 years of age.

IMPACT

In the large multi-center Extremely Low Gestational Age Newborn (ELGAN) cohort, sustained elevation of neonatal levels of inflammation-related proteins was not consistently associated with asthma or obesity outcomes at 10 or 15 years of age. This finding contrasts with reported associations of perinatal inflammation with obesity at 2 years and neurodevelopmental disorders at 2-15 years in the ELGANs, suggesting that unlike neurodevelopment, peripubertal obesity and asthma may be driven by later childhood exposures. Future research on perinatal mechanisms of childhood asthma and obesity should account for both fetal and later exposures and pathways in addition to inflammation at birth.

Retinopathy of prematurity and neurodevelopmental outcome and quality of life at 10 years of age

Objective

In a cohort of 10-year-old children born extremely preterm, we evaluated the hypothesis that increasing severity of retinopathy of prematurity (ROP) is associated with increasing frequency of unfavorable neurodevelopmental and quality of life outcomes.

Study Design

Study participants were classified according to the severity of ROP. At 10 years of age, their neurocognitive abilities, academic achievement, and gross motor function were assessed, and they were evaluated for autism spectrum disorder, anxiety, depression, and quality of life.

Results

After adjustment for sample attrition and confounders, only the association with lower quality of life persisted. Increasing severity of visual impairment was associated with worse neurodevelopmental outcomes and lower quality of life.

Conclusion

Among extremely preterm children, severity of visual impairment, but not severity of ROP, was associated with adverse neurodevelopmental outcomes at 10 years of age. Both severe ROP and more severe visual impairment were associated with lower quality of life.

Noise phenomena in distress cries of term and very preterm infants at term-equivalent age

BACKGROUND AND AIM

To examine whether the noise components in distress cries of term infants differed from very preterm infants whose cries were collected at a comparable "corrected" gestational age.

METHODS

Distress cries were collected from 20 term and 20 preterm infants. The cries were acoustically examined for the occurrence of aperiodic phonatory behavior within and across moments of crying.

RESULTS

The findings indicated no significant differences between term and preterm infants at term age in the occurrence of noise.

CONCLUSIONS

Distress cries of both term and term-equivalent preterm infants appear to contain high instances of phonatory noise. The high arousal associated with distress crying and associated increase in subglottal pressure appeared to influence both term and term-equivalent preterm infants similarly.

Growth and Neurodevelopmental Outcomes of Preterm Infants Born < 26 Weeks Gestation before and after Implementation of a Nutrition-Care Bundle

BACKGROUND

This study aimed to assess the impact of a nutrition-care bundle on growth and neurodevelopmental outcomes of micro-preterm infants born in a level III neonatal intensive care unit (NICU) by two years corrected age.

METHODS

A nutrition-care bundle emphasizing the prompt initiation of parenteral nutrition at birth, initiation of enteral feeds within 6 h after birth, and early addition of human milk fortifiers was implemented in 2015 for infants born < 26 weeks gestation. This before-and-after study evaluated growth and neurodevelopmental outcomes in infants born between 2012-2013 (before-nutrition-bundle, BNB) and 2016-2017 (after-nutrition-bundle, ANB).

RESULTS

A total of 145 infants were included in the study. Infants in the ANB group (n = 73) were smaller (birthweight and gestational age), and there were more male infants and multiples included compared to the BNB group (n = 72). Enteral feeds and fortifiers started earlier in the ANB group. Growth velocity and weight z-score changes were similar in both groups during NICU stay and post-discharge. Systemic steroid use, but not cohort, was linked to lower Bayley scores across all domains.

CONCLUSIONS

Implementing a nutrition-care bundle was not consistently associated with improved weight gain and neurodevelopmental outcomes in the micro-preterm infant population, possibly due to ongoing high-quality nutritional care by the clinical team.

Despite Recovery from Necrotizing Enterocolitis Infants Retain a Hyperinflammatory Response to Injury

Background

Necrotizing enterocolitis (NEC) is the leading gastrointestinal cause of death of premature neonates. NEC is associated with prematurity, a hyperinflammatory response, and dysregulation of intestinal barrier function. We hypothesize that patients with NEC will have, and continue to have after recovery, an increased hyperinflammatory intestinal response compared to those patients without NEC.

Methods

Neonates with NEC, those that have recovered from NEC, and those without NEC undergoing intestinal resections had specimens collected and snap frozen or generated into enteroids. The enteroids were treated with 100ug/mL lipopolysaccharide (LPS) and subjected to 24 hr of hypoxia together, then compared with untreated controls. Expression of Tumor Necrosis Factor (TNF-α) and interleukin 8 (IL-8) were evaluated via RT-qPCR and ELISA to measure inflammatory response. ANOVA determined statistical significance (p<0.05).

Results

There was no difference in inflammatory markers in recovered NEC tissue compared to non-NEC tissue on RTqPCR (p=0.701 TNF-α and 0.861 IL-8). However, recovered NEC enteroids demonstrate elevated levels of inflammatory markers after treatment compared to non-NEC enteroids after treatment on RTqPCR (p=0.0485 TNF-α, p=0.0057 IL-8) and ELISA (p=0.0354 TNF-α, p=0.0011 IL-8). Recovered NEC enteroids that underwent treatment demonstrated increased inflammatory markers compared to recovered NEC enteroids without treatment on RTqPCR (p=0.0045 TNF-α, p=0.0002 IL-8) and ELISA (p=0.034 TNF-α, p=0.0002 IL-8) suggesting a heightened inflammatory response to a second hit.

Conclusion

Intestinal tissue resected from neonates with NEC has an elevated hyperinflammatory response compared to neonates recovered from NEC and neonates without NEC. Enteroids generated from patients that have recovered from NEC have a heightened inflammatory response in response to NEC inducing stimuli compared to controls. This tendency towards an increased hyperinflammatory state may be correlated with an infant's proclivity to develop NEC and demonstrates the significance of a second hit on this tissue creating a heightened inflammatory response. This could be correlated with the impact and trajectory of an illness post recovery from NEC.

Factors Contributing to the Health of 0- to 5-Year-Old Low-Birth-Weight Children in the United States: Application of the Multiple Disadvantage Model

This secondary data analysis of 1731 low-birth-weight children and their parents in the United States investigated children's health and its associations with social disorganization, social structural factors, social relationships, health/mental health, and access to health insurance/services. The study drew on data from the 2021 National Survey of Children's Health. Logistic regression yielded results showing low-birth-weight children's excellent/very good/good health to be associated positively with parents' education and health. In turn, child health was associated negatively with being Black, having a family income at or below the 100% federal poverty level, difficulty parenting the child, child chronic health condition(s), parent mental health, and substance use in the family. The implications of the present findings in terms of interventions promoting maternal and child health as well as participation in government assistance programs for low-income families are discussed.

Fertility treatment increases the risk of preterm birth independent of multiple gestations

Objective

To investigate the complex interplay between fertility treatment, multiple gestations, and prematurity.

Design

Retrospective cohort study linking the national Center for Disease Control and Prevention infant birth and death data from 2014 to 2018.

Setting

National database from Center of Disease Control and Prevention.

Patients

In total, 19,454,155 live-born infants with gestational ages 22-44 weeks, 114,645 infants born using non IVF fertility treatment (NIFT), and 179,960 via assisted reproductive technology (ART).

Intervention

Noninvasive fertility treatment or ART vs. spontaneously conceived pregnancies.

Main Outcome Measures

The main outcome assessed was prematurity. Formal mediation analysis was conducted to calculate the percentage mediated by multiple gestations.

Results

Newborns born using NIFT or ART compared with those with no fertility treatment had a higher incidence of multiple gestation (no fertility treatment = 3.0%; NIFT = 24.7%; ART = 32.7%; P<.001) and prematurity (no fertility treatment = 11.2%; NIFT = 23.4%; ART = 28.4%; P<.001). Mediation analysis demonstrates that 76.8% (95% confidence interval [CI], 75.2%-78.1%) of the effect of NIFT on prematurity was mediated through multiple gestations. Similarly, 71.2% (95% CI, 70.8%-72.7%) of the effect of ART on prematurity is mediated through multiple gestation. However, the direct effect of NIFT on prematurity is 20.4% (95% CI, 19.0%-22.0%). The direct effect of ART was 24.7% (95% CI, 23.7%-25.6%).

Conclusion

A significant proportion of prematurity associated with fertility treatment is mediated by the treatment itself, independent of multiple gestations.

Persistent Proclivity to a Proinflammatory State in a Human Enteroid Model of Necrotizing Enterocolitis

Background: Necrotizing enterocolitis (NEC) is a devastating disease of premature neonates with substantial morbidity and mortality. Necrotizing enterocolitis is associated with prematurity, a hyperinflammatory response, and dysregulation of intestinal barrier function. We hypothesize that patients with NEC will have an increased hyperinflammatory intestinal response compared with those without NEC. Patients and Methods: Enteroids were generated from intestinal tissue from neonates undergoing resection. They were treated with 100 mcg/mL lipopolysaccharide (LPS), subjected to 24 hours of hypoxia inducing experimental NEC, then compared with untreated controls. Expression of tumor necrosis factor (TNF-α) and interleukin 8 (IL-8) were evaluated via reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA) to measure inflammatory response. Analysis of variance (ANOVA) determined statistical significance (p < 0.05). Results: Treated NEC-derived enteroids expressed significantly higher levels of IL-8 (RT-qPCR, p = 0.003; ELISA, p = 0.0002) compared with untreated NEC-derived enteroids with an increase in inflammatory marker concentration in those with a greater degree of prematurity (ELISA, p = 0.0015). A higher level of IL-8 was seen in NEC-derived enteroids compared with control after treatment (RT-qPCR, p = 0.024). Tumor necrosis factor-α levels were elevated in treated NEC-derived enteroids compared with untreated NEC-derived enteroids (RT-qPCR, p = 0.006; ELISA, p = 0.002) and compared with treated non-NEC-derived enteroids (RT-qPCR, p = 0.025; ELISA, p < 0.0001). Conclusions: Enteroids generated from neonates with NEC have an elevated hyperinflammatory response in response to NEC-inducing stimuli compared with controls. Enteroids generated from neonates with NEC with a greater degree of prematurity have a larger increase in inflammatory markers. This tendency toward a hyperinflammatory state may be correlated with an infant's proclivity to develop NEC and further demonstrates the hyperinflammatory state of prematurity.

Sexually dimorphic methylation patterns characterize the placenta and blood from extremely preterm newborns

BACKGROUND

Health outcomes among children born prematurely are known to be sexually dimorphic, with male infants often more affected, yet the mechanism behind this observation is not clear. CpG methylation levels in the placenta and blood also differ by sex and are associated with adverse health outcomes. We contrasted CpG methylation levels in the placenta and neonatal blood (n = 358) from the Extremely Low Gestational Age Newborn (ELGAN) cohort based on the EPIC array, which assays over 850,000 CpG sites across the epigenome. Sex-specific epigenome-wide association analyses were conducted for the placenta and neonatal blood samples independently, and the results were compared to determine tissue-specific differences between the methylation patterns in males and females. All models were adjusted for cell type heterogeneity. Enrichment pathway analysis was performed to identify the biological functions of genes related to the sexually dimorphic CpG sites.

RESULTS

Approximately 11,500 CpG sites were differentially methylated in relation to sex. Of these, 5949 were placenta-specific and 5361 were blood-specific, with only 233 CpG sites overlapping in both tissues. For placenta-specific CpG sites, 90% were hypermethylated in males. For blood-specific CpG sites, 95% were hypermethylated in females. In the placenta, keratinocyte differentiation biological pathways were enriched among the differentially methylated genes. No enrichment pathways were observed for blood.

CONCLUSIONS

Distinct methylation patterns were observed between male and female children born extremely premature, and keratinocyte differentiation pathways were enriched in the placenta. These findings provide new insights into the epigenetic mechanisms underlying sexually dimorphic health outcomes among extremely premature infants.

When a birth cohort grows up: challenges and opportunities in longitudinal developmental origins of health and disease (DOHaD) research

High-quality evidence from prospective longitudinal studies in humans is essential to testing hypotheses related to the developmental origins of health and disease. In this paper, the authors draw upon their own experiences leading birth cohorts with longitudinal follow-up into adulthood to describe specific challenges and lessons learned. Challenges are substantial and grow over time. Long-term funding is essential for study operations and critical to retaining study staff, who develop relationships with participants and hold important institutional knowledge and technical skill sets. To maintain contact, we recommend that cohorts apply multiple strategies for tracking and obtain as much high-quality contact information as possible before the child's 18th birthday. To maximize engagement, we suggest that cohorts offer flexibility in visit timing, length, location, frequency, and type. Data collection may entail multiple modalities, even at a single collection timepoint, including measures that are self-reported, research-measured, and administrative with a mix of remote and in-person collection. Many topics highly relevant for adolescent and young adult health and well-being are considered to be private in nature, and their assessment requires sensitivity. To motivate ongoing participation, cohorts must work to understand participant barriers and motivators, share scientific findings, and provide appropriate compensation for participation. It is essential for cohorts to strive for broad representation including individuals from higher risk populations, not only among the participants but also the staff. Successful longitudinal follow-up of a study population ultimately requires flexibility, adaptability, appropriate incentives, and opportunities for feedback from participants.

Implementation of Early Detection and Intervention for Cerebral Palsy in High-Risk Infant Follow-Up Programs: U.S. and Global Considerations

Early detection and intervention for cerebral palsy is best practice for all high-risk infants according to international guidelines, consensus statements and research-supported evidence. It allows support for families and optimization of developmental trajectories into adulthood. All phases of implementation of CP early detection can be found across the world in high-risk infant follow-up programs, demonstrating feasibility and acceptability through standardized implementation science. The largest clinical network for CP early detection and intervention in the world has now sustained an average age at detection less than 12 months corrected age for more than 5 years. Targeted referrals and interventions for CP can now be offered to patients in optimal periods of neuroplasticity, and new therapies researched as the age of detection decreases. Implementation of guidelines and incorporation of rigorous CP research studies both allow high-risk infant follow-up programs to fulfill their mission of improving outcomes of those with the most vulnerable developmental trajectories from birth.

Child and family factors associated with positive outcomes among youth born extremely preterm

BACKGROUND

To analyze the relationship of child behavioral and communication disorders, and adverse family events, to later-in-life child health and cognitive function among youth born extremely preterm.

METHODS

The study participants were 694 children enrolled in the Extremely Low Gestational Age Newborn Study. At ages 2 and 10, we assessed internalizing and externalizing behaviors, and at age 10, we assessed adverse life events within the family. Associations were evaluated between these child and family factors and positive child health at age 10 years, and global health and cognitive function at age 15 years.

RESULTS

Lower T-scores for internalizing or externalizing behaviors at age 2 were associated with more positive health at age 10. The absence of internalizing behaviors at age 10 was associated with better global child health and better cognitive function at age 15. The absence of communication deficits at age 10 was associated with better cognitive function at age 15. The absence of parent job loss was associated with better global child health at age 15.

CONCLUSION

Among individuals born extremely preterm, child health and cognitive outcomes might be improved by timely interventions to address child behavioral symptoms and the impact of adverse life events in the family.

IMPACT

The absence of child behavioral and communication disorders, and adverse family events, were associated with more positive health, higher global health, and better cognitive function among youth born extremely preterm. Interventions to address behavioral disorders in early childhood, and to reduce the impact of adverse life events on the family, might promote improved health and developmental outcomes for adolescents born extremely preterm.

Synthetic MR Imaging-Based WM Signal Suppression Identifies Neonatal Brainstem Pathways in Vivo

BACKGROUND AND PURPOSE

Multidynamic multiecho sequence-based imaging enables investigators to reconstruct multiple MR imaging contrasts on the basis of a single scan. This study investigated the feasibility of synthetic MRI-based WM signal suppression (syWMSS), a synthetic inversion recovery approach in which a short TI suppresses myelin-related signals, for the identification of early myelinating brainstem pathways.

MATERIALS AND METHODS

Thirty-one cases of neonatal MR imaging, which included multidynamic multiecho data and conventionally acquired T1- and T2-weighted sequences, were analyzed. The multidynamic multiecho postprocessing software SyMRI was used to generate syWMSS data (TR/TE/TI = 3000/5/410 ms). Two raters discriminated early myelinating brainstem pathways (decussation of the superior cerebellar peduncle, medial lemniscus, central tegmental tract, and medial longitudinal fascicle [the latter 3 assessed at the level of the pons]) on syWMSS data and reference standard contrasts.

RESULTS

On the basis of syWMSS data, the decussation of the superior cerebellar peduncle (31/31); left/right medial lemniscus (31/31; 30/31); left/right central tegmental tract (19/31; 20/31); and left/right medial longitudinal fascicle (30/31) were reliably identified by both raters. On the basis of T1-weighted contrasts, the decussation of the superior cerebellar peduncle (14/31); left/right medial lemniscus (22/31; 16/31); left/right central tegmental tract (1/31); and left/right medial longitudinal fascicle (9/31; 8/31) were reliably identified by both raters. On the basis of T2-weighted contrasts, the decussation of the superior cerebellar peduncle (28/31); left/right medial lemniscus (16/31; 12/31); left/right central tegmental tract (23/31; 18/31); and left/right medial longitudinal fascicle (15/31; 14/31) were reliably identified by both raters.

CONCLUSIONS

syWMSS data provide a feasible imaging technique with which to study early myelinating brainstem pathways. MR imaging approaches that use myelin signal suppression contribute to a more sensitive assessment of myelination patterns at early stages of cerebral development.

RSV-related hospitalization and outpatient palivizumab use in very preterm (born at <29 wGA) infants: 2003-2020

Respiratory syncytial virus (RSV) is a leading cause of bronchiolitis and pneumonia in children under one year and a leading cause of infant hospitalization. Palivizumab was approved by the FDA in 1998 as RSV immunoprophylaxis to prevent severe RSV disease in children with specific health conditions and those born at <35 weeks gestational age (wGA). This study compared RSV-related hospitalization (RSVH) and RSVH characteristics in very preterm (<29 wGA) and term (>37 wGA) infants. Using the MarketScan Commercial and Multi-State Medicaid administrative claims databases, infants born between 7/1/2003 and 6/30/2020 were identified and classified as very preterm or term. Infants with evidence of health conditions, such as congenital heart disease and cystic fibrosis, were excluded. During 2003-2020 RSV seasons (November to March), claims incurred by infants while they were <12 months old were evaluated for outpatient administration of palivizumab and RSVH. The study included 40,123 very preterm infants and 4,421,942 term infants. Rate of RSVH in very preterm infants ranged 1.5-3.8 per 100 infant-seasons in commercially insured infants and 3.5-8.4 in Medicaid insured infants and were inversely related to wGA at birth. Relative risk of RSVH in very preterm was 3-4 times higher, and ICU admissions and mechanical ventilation were more common during RSVH in very preterm infants relative to term infants. However, these outcomes were less common or less severe in very preterm infants who received outpatient palivizumab administration, despite evidence of higher baseline risk of RSVH in these infants.

A mixed-effects two-part model for twin-data and an application on identifying important factors associated with extremely preterm children's health disorders

Our recent studies identifying factors significantly associated with the positive child health index (PCHI) in a mixed cohort of preterm-born singletons, twins, and triplets posed some analytic and modeling challenges. The PCHI transforms the total number of health disorders experienced (of the eleven ascertained) to a scale from 0 to 100%. While some of the children had none of the eleven health disorders (i.e., PCHI = 1), others experienced a subset or all (i.e., 0 ≤PCHI< 1). This indicates the existence of two distinct data processes-one for the healthy children, and another for those with at least one health disorder, necessitating a two-part model to accommodate both. Further, the scores for twins and triplets are potentially correlated since these children share similar genetics and early environments. The existing approach for analyzing PCHI data dichotomizes the data (i.e., number of health disorders) and uses a mixed-effects logistic or multiple logistic regression to model the binary feature of the PCHI (1 vs. < 1). To provide an alternate analytic framework, in this study we jointly model the two data processes under a mixed-effects two-part model framework that accounts for the sample correlations between and within the two data processes. The proposed method increases power to detect factors associated with disorders. Extensive numerical studies demonstrate that the proposed joint-test procedure consistently outperforms the existing method when the type I error is controlled at the same level. Our numerical studies also show that the proposed method is robust to model misspecifications and it is applicable to a set of correlated semi-continuous data.