Neonatal stress exposure and DNA methylation of stress-related and neurodevelopmentally relevant genes: An exploratory study

BACKGROUND

Stress exposure during Neonatal Intensive Care Unit (NICU) stay may have long-lasting effects on neurodevelopmental outcomes in extremely preterm infants. Altered DNA methylation of stress-related and neurodevelopmentally relevant genes may be an underlying mechanism.

AIMS

This exploratory study aimed to investigate the association between neonatal stress exposure and DNA methylation in these genes at two different time points: early during the NICU stay (7-14 days after birth) and later, at discharge from the NICU.

SUBJECTS

We included 45 extremely preterm infants in this prospective cohort study, gestational age 24-30 weeks.

OUTCOME MEASURES

We collected fecal samples at days 7-14 (n = 44) and discharge (n = 28) and determined DNA methylation status in predefined regions of NR3C1, SLC6A4, HSD11B2, OPRM1, SLC7A5, SLC1A2, IGF2, NNAT, BDNF and GABRA6 using pyrosequencing. Because of low DNA concentrations in some fecal samples, we could do so in 25-50 % of collected samples. We prospectively quantified daily neonatal stress exposure using the Neonatal Infant Stressor Scale (NISS) and explored associations between cumulative NISS scores and average DNA methylation status.

RESULTS

Rates of methylation of most genes were not statistically different between day 7-14 and discharge, except for OPRM1. We found moderately high and mostly negative correlation coefficients upon discharge with the cumulative NISS for the NR3C1, SLC6A4, SLC1A2, IGF2, BDNF and OPRM1 genes, albeit not statistically significant.

CONCLUSIONS

Findings suggest that expression of stress-related and neurodevelopmentally relevant genes may be differently regulated following higher neonatal stress exposure. Larger studies should challenge the findings of this study and ideally test the effects on gene expression.

Health-related quality of life in adults born extremely preterm or with extremely low birth weight in the postsurfactant era: a longitudinal cohort study

OBJECTIVES

To compare health-related quality of life (HRQoL) at 25 and 18 years in individuals born extremely preterm (EP, <28 weeks' gestation) or with extremely low birth weight (ELBW, birth weight <1000 g) with term-born (≥37 weeks) controls. Within the EP/ELBW cohort, to determine whether HRQoL differed between those with lower and higher IQs.

METHODS

HRQoL was self-reported using the Health Utilities Index Mark 3 (HUI3) at 18 and 25 years by 297 EP/ELBW and 251 controls born in 1991-1992 in Victoria, Australia. Median differences (MDs) between groups were estimated using multiple imputation to handle missing data.

RESULTS

Adults born EP/ELBW had lower HRQoL (median utility 0.89) at 25 years than controls (median utility 0.93, MD -0.040), but with substantial uncertainty in the estimate (95% CI -0.088 to 0.008) and a smaller reduction at 18 years (MD -0.016, 95% CI -0.061 to 0.029). On individual HUI3 items, there was suboptimal performance on speech (OR 9.28, 95% CI 3.09 to 27.93) and dexterity (OR 5.44, 95% CI 1.04 to 28.45) in the EP/ELBW cohort. Within the EP/ELBW cohort, individuals with lower IQ had lower HRQoL compared with those with higher IQ at 25 (MD -0.031, 95% CI -0.126 to 0.064) and 18 years (MD -0.034, 95% CI -0.107 to 0.040), but again with substantial uncertainty in the estimates.

CONCLUSIONS

Compared with term-born controls, young adults born EP/ELBW reported poorer HRQoL, as did those with lower IQ compared with those with higher IQ in the EP/ELBW cohort. Given the uncertainties, our findings need corroboration.

Functional morphometry: non-invasive estimation of the alveolar surface area in extremely preterm infants

BACKGROUND

The main pathophysiologic characteristic of chronic respiratory disease following extremely premature birth is arrested alveolar growth, which translates to a smaller alveolar surface area (SA). We aimed to use non-invasive measurements to estimate the SA in extremely preterm infants.

METHODS

Paired measurements of the fraction of inspired oxygen and transcutaneous oxygen saturation were used to calculate the ventilation/perfusion ratio, which was translated to SA using Fick's law of diffusion. The SA was then adjusted using volumetric capnography.

RESULTS

Thirty infants with a median (range) gestational age of 26.3 (22.9-27.9) weeks were studied. The median (range) adjusted SA was 647.9 (316.4-902.7) cm2. The adjusted SA was lower in the infants who required home oxygen [637.7 (323.5-837.5) cm2] compared to those who did not [799.1 (444.2-902.7) cm2, p = 0.016]. In predicting the need for supplemental home oxygen, the adjusted SA had an area under the receiver operator characteristic curve of 0.815 (p = 0.017). An adjusted SA ≥688.6 cm2 had 86% sensitivity and 77% specificity in predicting the need for supplemental home oxygen.

CONCLUSIONS

The alveolar surface area can be estimated non-invasively in extremely preterm infants. The adjusted alveolar surface area has the potential to predict the subsequent need for discharge home on supplemental oxygen.

IMPACT

We describe a novel biomarker of respiratory disease following extremely preterm birth. The adjusted alveolar surface area index was derived by non-invasive measurements of the ventilation/perfusion ratio and adjusted by concurrent measurements of volumetric capnography. The adjusted alveolar surface area was markedly reduced in extremely preterm infants studied at 7 days of life and could predict the need for discharge home on supplemental oxygen. This method could be used at the bedside to estimate the alveolar surface area and provide an index of the severity of lung disease, and assist in monitoring, clinical management and prognosis.

Fragility and resilience: parental and family perspectives on the impacts of extreme prematurity

OBJECTIVES

Extremely preterm babies have a significant risk of neurodevelopmental impairment (NDI). There has been little investigation regarding the impact of prematurity on families. The objective of this study was to explore parental perspectives regarding the impact of prematurity on themselves/their family.

METHODS

Over 1 year, parents of children born <29 weeks' gestational age (GA) who were between 18 months old and 7 years old and came for their follow-up visit were invited to participate. They were asked to categorise the impacts of prematurity on their life and their family as positive, negative or both and to describe those impacts in their own words. Thematic analysis was performed by a multidisciplinary group, including parents. Logistic regression was performed to compare parental responses.

RESULTS

Among parents (n=248, 98% participation rate), most (74%) reported that their child's prematurity had both positive and negative impacts on their life or their family's life, while 18% reported only positive impacts and 8% only negative impacts. These proportions were not correlated with GA, brain injury, nor level of NDI. The positive impacts reported included: an improved outlook on life, such as gratitude and perspective (48%), stronger family relationships (31%) and the gift of the child (28%). The negative themes were stress and fear (42%), loss of equilibrium due to medical fragility (35%) and concerns about developmental outcomes including the child's future (18%).

CONCLUSION

Parents report both positive and negative impacts after an extremely preterm birth, independent of disability. These balanced perspectives should be included in neonatal research, clinical care and provider education.

Etiology and Mechanism of Intermittent Hypoxemia Episodes in Spontaneously Breathing Extremely Premature Infants

OBJECTIVE

To evaluate the mechanisms leading to intermittent hypoxemia (IH) episodes in spontaneously breathing extremely premature infants at 32 weeks and 36 weeks postmenstrual age (PMA).

METHODS

We studied spontaneously breathing premature infants born at 23-28 weeks of gestational age who presented with IH episodes while on noninvasive respiratory support at 32 or 36 weeks PMA. Daytime recordings of arterial oxygen saturation (SpO2), esophageal pressure, respiratory inductive plethysmography of the abdomen, chest wall, and their sum were obtained during 4 hours at 32 weeks and 36 weeks PMA. IH episodes (SpO2 <90% for ≥5 seconds) and severe IH episodes (SpO2 < 80% for ≥5 seconds) were classified as resulting from apnea, active exhalation and breath holding, reduced tidal volume (VT), or reduced respiratory rate (RR) during the preceding 60 seconds.

RESULTS

Fifty-one infants with a mean gestational age of 25.9 ± 1.5 weeks and a mean birth weight of 846 ± 185 g were included. Of these, 31 and 41 were included in the analysis at 32 weeks and 36 weeks PMA, respectively. At both 32 weeks and 36 weeks PMA, greater proportions of all IH episodes and severe IH episodes were associated with active exhalation and breath holding than with apnea, reduced RR, or reduced VT. The severity and duration of the IH episodes did not differ between mechanisms.

CONCLUSIONS

In this group of premature infants, the predominant mechanism associated with daytime IH was active exhalation and breath holding. This etiology is more closely associated with behavioral factors than abnormal respiratory control and can have implications for prevention.

Clinical usefulness of reintubation criteria in extremely preterm infants: a cohort study

OBJECTIVE

To describe the thresholds of instability used by clinicians at reintubation and evaluate the accuracy of different combinations of criteria in predicting reintubation decisions.

DESIGN

Secondary analysis using data obtained from the prospective observational Automated Prediction of Extubation Readiness study (NCT01909947) between 2013 and 2018.

SETTING

Multicentre (three neonatal intensive care units).

PATIENTS

Infants with birth weight ≤1250 g, mechanically ventilated and undergoing their first planned extubation were included.

INTERVENTIONS

After extubation, hourly O2 requirements, blood gas values and occurrence of cardiorespiratory events requiring intervention were recorded for 14 days or until reintubation, whichever came first.

MAIN OUTCOME MEASURES

Thresholds at reintubation were described and grouped into four categories: increased O2, respiratory acidosis, frequent cardiorespiratory events and severe cardiorespiratory events (requiring positive pressure ventilation). An automated algorithm was used to generate multiple combinations of criteria from the four categories and compute their accuracies in capturing reintubated infants (sensitivity) without including non-reintubated infants (specificity).

RESULTS

55 infants were reintubated (median gestational age 25.2 weeks (IQR 24.5-26.1 weeks), birth weight 750 g (IQR 640-880 g)), with highly variable thresholds at reintubation. After extubation, reintubated infants had significantly greater O2 needs, lower pH, higher pCO2 and more frequent and severe cardiorespiratory events compared with non-reintubated infants. After evaluating 123 374 combinations of reintubation criteria, Youden indices ranged from 0 to 0.46, suggesting low accuracy. This was primarily attributable to the poor agreement between clinicians on the number of cardiorespiratory events at which to reintubate.

CONCLUSIONS

Criteria used for reintubation in clinical practice are highly variable, with no combination accurately predicting the decision to reintubate.

The association of maternal overweight on long-term neurodevelopmental outcomes in premature infants (< 29 weeks) at 18-24 months corrected age

OBJECTIVE

To determine the association of maternal pre-pregnancy body mass index (BMI) and neurodevelopmental impairment (NDI) at 18-24 months corrected age (CA) in infants born < 29 weeks gestation.

STUDY DESIGN

Infants born between 2005 and 2015 at < 29 weeks gestation were included. BMI was categorized into BMI1 [18.5-24.9 kg/m2], BMI2 [25-29.9 kg/m2], BMI3 [ ≥ 30 kg/m2]. Primary outcome was death or NDI (Bayley-III scores < 85, cerebral palsy, hearing or visual impairment). Univariate and multivariate analysis were used.

RESULTS

There were 315 infants in BMI1, 235 in BMI2, and 147 in BMI3 groups. Adjusted odds ratio (aOR) of death or NDI in BMI2 vs. BMI1 and BMI3 vs BMI1 groups were 1.33 (95% CI 0.86-2.06) and 0.76 (95% CI 0.47-1.22). Adjusted odds ratio of Bayley-III language composite < 85 was 2.06 (95% CI 1.28-3.32).

CONCLUSION

Pre-pregnancy BMI was not associated with death or NDI in extremely preterm infants. Infants born to overweight mothers had higher odds of low language scores.

Patent Ductus Arteriosus and Bronchopulmonary Dysplasia-Associated Pulmonary Hypertension: A Bayesian Meta-Analysis

Importance

Bronchopulmonary dysplasia (BPD) is often associated with pulmonary vascular disease and secondary pulmonary hypertension (PH). The pathogenesis of BPD-associated PH (BPD-PH) is complex and involves prenatal and postnatal factors that disrupt pulmonary vascular development, and patent ductus arteriosus (PDA) is a factor potentially associated with risk of BPD-PH that has been identified in very recent studies.

Objective

To explore the association of PDA with BPD-PH using a bayesian model-averaged (BMA) meta-analysis of studies.

Data Sources

PubMed and Embase were searched up to April 2023. Key search terms included BPD and PH.

Study Selection

Studies examining infants with gestational age 32 weeks or less and reporting data on PDA and risk of BPD-PH.

Data Extraction and Synthesis

This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and the Meta-Analysis of Observational Studies in Epidemiology reporting guidelines. Two independent reviewers extracted data, with a third reviewer checking for accuracy and completeness. Data pooling and effect size calculations were performed by BMA.

Main Outcomes and Measures

The primary outcome was BPD-PH. BMA was used to calculate Bayes factors (BFs). The BF10 is the ratio of the probability of the data under the alternative hypothesis (H1, association of PDA with BPD-HP) over the probability of the data under the null hypothesis (H0).

Results

A total of 32 studies (8513 infants) were included. BMA showed that the evidence in favor of H1 was weak for any PDA (BF10 = 2.90; 10 studies), moderate for hemodynamically significant PDA (BF10 = 3.77; 3 studies), and extreme for surgically ligated or catheter-occluded PDA (BF10 = 294.9; 16 studies). In contrast, the evidence in favor of H0 was weak for medically treated PDA (BF10 = 0.55; 6 studies). In addition, BMA found strong evidence in favor of H1 when prolonged exposure to PDA was analyzed as a dichotomous variable (BF10 = 11.80; 6 studies) and extreme evidence (BF10 = 113.60; 3 studies) when PDA exposure time was analyzed as a continuous variable.

Conclusions and Relevance

In this bayesian meta-analysis, the data suggest that prolonged exposure to PDA might be associated with increased risk of pulmonary vascular disease in extremely preterm infants. This highlights the need to monitor for PH in high-risk preterm infants with prolonged exposure to PDA and to incorporate PH risk into clinical decisions regarding PDA management.

Use of term reference infants in assessing the developmental outcome of extremely preterm infants: lessons learned in a multicenter study

OBJECTIVE

Extremely preterm (EP) impairment rates are likely underestimated using the Bayley III norm-based thresholds scores and may be better assessed relative to concurrent healthy term reference (TR) infants born in the same hospital.

STUDY DESIGN

Blinded, certified examiners in the Neonatal Research Network (NRN) evaluated EP survivors and a sample of healthy TR infants recruited near the 2-year assessment age.

RESULTS

We assessed 1452 EP infants and 183 TR infants. TR-based thresholds showed higher overall EP impairment than Bayley norm-based thresholds (O.R. = 1.86; [95% CI 1.56-2.23], especially for severe impairment (36% vs. 24%; p ≤ 0.001). Difficulty recruiting TR patients at 2 years extended the study by 14 months and affected their demographics.

CONCLUSION

Impairment rates among EP infants appear to be substantially underestimated from Bayley III norms. These rates may be best assessed by comparison with healthy term infants followed with minimal attrition from birth in the same centers.

CLINICALTRIALS

GOV ID

Term Reference (under the Generic Database Study): NCT00063063.

Lung function deficits and bronchodilator responsiveness at 12 years of age in children born very preterm compared with controls born at term

INTRODUCTION

Very preterm birth is associated with lung function impairment later in life, but several aspects have not been studied. We aimed to comprehensively assess lung function at school age in very preterm infants and term controls, with special emphasis on bronchopulmonary dysplasia (BPD), sex, and bronchodilator response.

METHODS

At 12 years of age, 136 children born very preterm (85 with and 51 without BPD) and 56 children born at term performed spirometry, body plethysmography, impulse oscillometry, measurement of diffusion capacity, and multiple breath washout, before and after bronchodilator inhalation.

RESULTS

Airway symptoms and a diagnosis of asthma were more common in children born very preterm. These children had more airflow limitation, seen as lower forced expiratory volume in 1 s (FEV1 ) (p < .001), FEV1 /forced vital capacity (FVC) (p = .011), and mean forced expiratory flow between 25% and 75% of FVC (p < .001), and a higher total and peripheral airway resistance compared with term-born controls. There was no difference in total lung capacity but air trapping and lung clearance index were higher in children born very preterm. Diffusion capacity was lower in children born very preterm, especially in those with a diagnosis of BPD. In most other tests, the differences between preterm-born children with or without BPD were smaller than between children born preterm versus at term. Boys born preterm had more lung function deficits than preterm-born girls. In children born very preterm, airway obstruction was to a large extent reversible.

CONCLUSION

At 12 years of age, children born very preterm had lower lung function than children born at term in most aspects and there was only little difference between children with or without BPD. Airway obstruction improved markedly after bronchodilator inhalation.

The Impact of Intraventricular Hemorrhage and Periventricular Leukomalacia on Mortality and Neurodevelopmental Outcome in Very Preterm and Very Low Birthweight Infants: A Prospective Population-based Cohort Study

OBJECTIVE

To survey the incidence of intraventricular hemorrhage (IVH) and periventricular leukomalacia (PVL) by gestational age and to report the impact on mortality and neurodevelopmental outcome in very preterm/very low birthweight infants.

STUDY DESIGN

This was a population-based cohort study of 1927 very preterm/very low birthweight infants born in 2014-2016 and admitted to Flemish neonatal intensive care units. Infants underwent standard follow-up assessment until 2 years corrected age with the Bayley Scales of Infant and Toddler Development and neurological assessments.

RESULTS

No brain lesion was present in 31% of infants born at <26 weeks of gestation and 75.8% in infants born at 29-32 weeks of gestation. The prevalence of low-grade IVH/PVL (grades I and II) was 16.8% and 12.7%, respectively. Low-grade IVH/PVL was not related significantly to an increased likelihood of mortality, motor delay, or cognitive delay, except for PVL grade II, which was associated with a 4-fold increase in developing cerebral palsy (OR, 4.1; 95% CI, 1.2-14.6). High-grade lesions (III-IV) were present in 22.0% of the infants born at <26 weeks of gestational and 3.1% at 29-32 weeks of gestation, and the odds of death were ≥14.0 (IVH: OR, 14.0; 95% CI, 9.0-21.9; PVL: OR, 14.1; 95% CI, 6.6-29.9). PVL grades III-IV showed an increased odds of 17.2 for motor delay and 12.3 for cerebral palsy, but were not found to be associated significantly with cognitive delay (OR, 2.9; 95% CI, 0.5-17.5; P = .24).

CONCLUSIONS

Both the prevalence and severity of IVH/PVL decreased significantly with advancing gestational age. More than 75% of all infants with low grades of IVH/PVL showed normal motor and cognitive outcome at 2 years corrected age. High-grade PVL/IVH has become less common and is associated with adverse outcomes.

Motor performance and attention outcomes in children born very preterm

AIM

To examine the relationship between motor performance and attention in children born very preterm and at term, and investigate the presence of individual profiles of motor and attention performance.

METHOD

Attention and motor performance at 7 and 13 years were assessed in 197 children born very preterm (52.5% male) and 69 children born at term (47.8% male) between 2001 and 2003. Linear regression models were fitted including an interaction term for birth group. Subgroups of children with similar attention and motor performance profiles were identified using latent profile analysis.

RESULTS

Balance was positively associated with all attention outcomes at both ages (p < 0.006). There were specific birth group interactions for aiming and catching and manual dexterity with attention at 13 years, with positive associations observed only for children born very preterm (p < 0.001). At 7 years, three profiles were observed: average attention and motor functioning; average motor functioning and low attention functioning; and low attention and motor functioning. At 13 years, two profiles of average attention and motor functioning emerged, as well as one profile of below-average attention and motor functioning. Children born very preterm were overrepresented in the lower functioning profiles (born very preterm 56%; born at term 29%).

INTERPRETATION

Motor functioning at age 7 years may be a useful marker of later attention skills, particularly for children born very preterm who are at greater risk of poorer long-term cognitive outcomes.

WHAT THIS PAPER ADDS

Balance was positively associated with attention in children born very preterm and at term. Relationships between motor performance and attention at age 13 years differed between children born very preterm and at term. Heterogeneous motor functioning and attention outcomes were noted for children born very preterm and at term. Children born very preterm were more likely to have lower attention and motor functioning profiles than children born at term. There was greater movement in motor functioning and attention profiles between the ages of 7 and 13 years in children born very preterm.

Are the current feeding volumes adequate for the growth of very preterm neonates?

Postnatal growth failure, a common problem in very preterm neonates associated with adverse neurodevelopmental outcome, has recently been shown not to be inevitable. There is a wide discussion regarding feeding practices of very preterm neonates, specifically regarding feeding volumes and nutrients supply to avoid postnatal growth failure. Current guidelines recommend an energy intake of 115–140 kcal /kg per d with a considerably higher upper limit of 160 kcal/kg per d. The feeding volume corresponding to this energy supply is not higher than 200 ml/kg in most cases. From the other side, randomised and observational studies used higher feeding volumes, and these were associated with better weight gain and growth, while no complications were noted. Taking into account the above, nutritional practices should be individualised in each very and extremely preterm infant trying to reduce postnatal growth failure, pointing out that available data are inconclusive regarding the effect of high-volume feeds on growth. Large clinical trials are necessary to conclude in the best feeding practices of very preterm neonates.

Magnetic Resonance Imaging-Based Reference Values for Two-Dimensional Quantitative Brain Metrics in a Cohort of Extremely Preterm Infants

INTRODUCTION

Cerebral magnetic resonance imaging (cMRI) is an important diagnostic tool in neonatology. In addition to qualitative analysis, quantitative measurements may help identify infants with impaired brain growth. This study aimed to create reference values for brain metrics of various brain areas in neonates without major brain injuries born before 28 weeks of gestation.

METHODS

This retrospective study analyzes cMRI imaging data of high-risk patients without severe brain pathologies at term-equivalent age, collected over 4 years since November 2017. Nineteen brain areas were measured, reference values created, and compared to published values from fetal and postnatal MRI. Furthermore, correlations between brain metrics and gestational age at birth were evaluated.

RESULTS

A total of 174 cMRI examinations were available for analysis. Reference values including cut-offs for impaired brain growth were established for different gestational age groups. There was a significant correlation between gestational age at birth and larger "tissue" parameters, as well as smaller "fluid" parameters, including intracerebral and extracerebral spaces.

DISCUSSION

With quantitative brain metrics infants with impaired brain growth might be detected earlier. Compared to preexisting reference values, these are the first of a contemporary collective of extremely preterm neonates without severe brain injuries. Measurements can be easily performed by radiologists as well as neonatologists without specialized equipment or computational expertise.

CONCLUSION

Two-dimensional cMRI brain measurements at term-equivalent age represent an easy and reliable approach for the evaluation of brain size and growth in infants at high risk for neurodevelopmental impairment.

Parental Experiences of Neonatal Care: A Nationwide Study on Determinants of Excellence

INTRODUCTION

Infant- and family-centered developmental care can reduce adverse outcomes in both infants and parents. Parents' experiences of the care and staff treatment remain to be evaluated.

METHODS

Parents of infants admitted to neonatal units in Sweden from July 2020 to May 2022 responded to a questionnaire with standardized questions about in-hospital care. Exposures were hospital, gestational age, length of hospital stay, unit level, and bed density. The proportions of parents rating aspects of neonatal care as excellent, defined as five on a Likert scale, and the determinants of excellence were described. The results were benchmarked with ratings in adult somatic care.

RESULTS

A total of 4,475/13,108 (34%) parents responded. The ratings of excellent care varied by question from 65% to 90%. The largest variation in excellence between neonatal units (range 43-80%) was found for "participation and involvement." The proportion of excellence was significantly lower among parents of extremely preterm infants. Confidence in the staff was lower in parents of extremely preterm infants than in parents of term infants (56% vs. 83%). Longer hospital stays affected the experience of neonatal care adversely, whereas level of care and bed density were overall unrelated to the parental experience. Parents in neonatal care rated the care as excellent to a higher extent than patients cared for in adult medicine.

CONCLUSION

A majority of parents rated neonatal care in Sweden as excellent. The less frequent ratings of excellence among parents of extremely preterm infants indicate that more could be done to optimize parental involvement and support.

[Recent research on the long-term neurodevelopmental outcomes of very preterm infants]

With the increase in the survival rate of very preterm infants, the long-term neurodevelopmental outcomes of such infants have attracted more and more attention. Very preterm infants tend to develop movement disorders and psychological and behavioral problems, including cerebral palsy, developmental coordination disorders, autism spectrum disorders, attention deficit hyperactivity disorders, specific learning disorders, and intellectual developmental disorders. It is of vital importance to improve the long-term prognosis of very preterm infants, and early comprehensive intervention measures can minimize disability and achieve optimal parenting outcomes. This article provides a review of the research progress on the long-term neurodevelopmental outcomes in extremely preterm infants.

[Risk factors and prognosis of hypotension within 72 hours after birth in extremely preterm infants]

OBJECTIVES

To investigate the risk factors and prognosis of hypotension within 72 hours after birth in extremely preterm infants.

METHODS

A retrospective analysis was conducted on clinical data of extremely preterm infants admitted to the Children's Hospital of Zhejiang University School of Medicine from January 2019 to April 2022. Based on the presence of hypotension within 72 hours after birth, the eligible infants were divided into a hypotension group (41 cases) and a normotension group (82 cases). The clinical characteristics, echocardiographic parameters within 72 hours after birth, and early complications were compared between the two groups. Multivariate logistic regression analysis was used to explore the risk factors for hypotension within 72 hours after birth, and receiver operating characteristic curve analysis was performed to evaluate the predictive value of relevant indicators for the occurrence of hypotension within 72 hours after birth in the preterm infants.

RESULTS

The proportion of infants who required medication or surgical closure of patent ductus arteriosus (PDA), the proportions of infants with intraventricular hemorrhage ≥ grade III and severe pulmonary hemorrhage, and the mortality rate within 7 days in the hypotension group were significantly higher than those in the normotension group (P<0.05). Multivariate logistic regression analysis showed that lower birth weight, larger PDA diameter, and hemodynamically significant PDA were risk factors for the occurrence of hypotension within 72 hours after birth in extremely preterm infants (P<0.05). The receiver operating characteristic curve analysis showed that the combination of birth weight, PDA diameter, and hemodynamically significant PDA had an area under the curve of 0.873 (95%CI: 0.802-0.944, P<0.05) for predicting hypotension within 72 hours after birth, with a sensitivity of 73.2% and specificity of 91.5%.

CONCLUSIONS

Hypotension within 72 hours after birth is closely related to birth weight and PDA, and increases the risk of early severe complications and mortality in extremely preterm infants.

Indirect evidence for altered dopaminergic neurotransmission in very premature-born adults

While animal models indicate altered brain dopaminergic neurotransmission after premature birth, corresponding evidence in humans is scarce due to missing molecular imaging studies. To overcome this limitation, we studied dopaminergic neurotransmission changes in human prematurity indirectly by evaluating the spatial co-localization of regional alterations in blood oxygenation fluctuations with the distribution of adult dopaminergic neurotransmission. The study cohort comprised 99 very premature-born (<32 weeks of gestation and/or birth weight below 1500 g) and 107 full-term born young adults, being assessed by resting-state functional MRI (rs-fMRI) and IQ testing. Normative molecular imaging dopamine neurotransmission maps were derived from independent healthy control groups. We computed the co-localization of local (rs-fMRI) activity alterations in premature-born adults with respect to term-born individuals to different measures of dopaminergic neurotransmission. We performed selectivity analyses regarding other neuromodulatory systems and MRI measures. In addition, we tested if the strength of the co-localization is related to perinatal measures and IQ. We found selectively altered co-localization of rs-fMRI activity in the premature-born cohort with dopamine-2/3-receptor availability in premature-born adults. Alterations were specific for the dopaminergic system but not for the used MRI measure. The strength of the co-localization was negatively correlated with IQ. In line with animal studies, our findings support the notion of altered dopaminergic neurotransmission in prematurity which is associated with cognitive performance.

Cerebral oximetry monitoring versus usual care for extremely preterm infants: a study protocol for the 2-year follow-up of the SafeBoosC-III randomised clinical trial

BACKGROUND

In the SafeBoosC-III trial, treatment guided by cerebral oximetry monitoring for the first 72 hours after birth did not reduce the incidence of death or severe brain injury in extremely preterm infants at 36 weeks' postmenstrual age, as compared with usual care. Despite an association between severe brain injury diagnosed in the neonatal period and later neurodevelopmental disability, this relationship is not always strong. The objective of the SafeBoosC-III follow-up study is to assess mortality, neurodevelopmental disability, or any harm in trial participants at 2 years of corrected age. One important challenge is the lack of funding for local costs for a trial-specific assessment.

METHODS

Of the 1601 infants randomised in the SafeBoosC-III trial, 1276 infants were alive at 36 weeks' postmenstrual age and will potentially be available for the 2-year follow-up. Inclusion criteria will be enrollment in a neonatal intensive care unit taking part in the follow-up study and parental consent if required by local regulations. We aim to collect data from routine follow-up programmes between the ages of 18 and 30 months of corrected age. If no routine follow-up has been conducted, we will collect informal assessments from other health care records from the age of at least 12 months. A local co-investigator blinded to group allocation will classify outcomes based on these records. We will supplement this with parental questionnaires including the Parent Report of Children's Abilities-Revised. There will be two co-primary outcomes: the composite of death or moderate or severe neurodevelopmental disability and mean Bayley-III/IV cognitive score. We will use a 3-tier model for prioritisation, based on the quality of data. This approach has been chosen to minimise loss to follow-up assuming that little data is better than no data at all.

DISCUSSION

Follow-up at the age of 2 years is important for intervention trials in the newborn period as only time can show real benefits and harms later in childhood. To decrease the risk of generalisation and data-driven biased conclusions, we present a detailed description of the methodology for the SafeBoosC-III follow-up study. As funding is limited, a pragmatic approach is necessary.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05134116 . Registered on 24 November 2021.

Caffeine versus other methylxanthines for the prevention and treatment of apnea in preterm infants

BACKGROUND

Methylxanthines, including caffeine, theophylline, and aminophylline, work as stimulants of the respiratory drive, and decrease apnea of prematurity, a developmental disorder common in preterm infants. In particular, caffeine has been reported to improve important clinical outcomes, including bronchopulmonary dysplasia (BPD) and neurodevelopmental disability. However, there is uncertainty regarding the efficacy of caffeine compared to other methylxanthines.

OBJECTIVES

To assess the effects of caffeine compared to aminophylline or theophylline in preterm infants at risk of apnea, with apnea, or in the peri-extubation phase.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, Epistemonikos, the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP), and clinicaltrials.gov in February 2023. We also checked the reference lists of relevant articles to identify additional studies.

SELECTION CRITERIA

Studies: randomized controlled trials (RCTs) and quasi-RCTs Participants: infants born before 34 weeks of gestation for prevention and extubation trials, and infants born before 37 weeks of gestation for treatment trials Intervention and comparison: caffeine versus theophylline or caffeine versus aminophylline. We included all doses and duration of treatment.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We evaluated treatment effects using a fixed-effect model with risk ratio (RR), risk difference (RD), and 95% confidence intervals (CI) for categorical data, and mean, standard deviation, and mean difference for continuous data. We used the GRADE approach to evaluate the certainty of evidence.

MAIN RESULTS

We included 22 trials enrolling 1776 preterm infants. The indication for treatment was prevention of apnea in three studies, treatment of apnea in 13 studies, and extubation management in three studies. In three studies, there were multiple indications for treatment, and in one study, the indication for treatment was unclear. In 19 included studies, the infants had a mean gestational age between 28 and 32 weeks and a mean birth weight between 1000 g and 1500 g. One study's participants had a mean gestational age of more than 32 weeks, and two studies had participants with a mean birth weight of 1500 g or more. Caffeine administrated for any indication may result in little to no difference in all-cause mortality prior to hospital discharge compared to other methylxanthines (RR 1.12, 95% CI 0.68 to 1.84; RD 0.02, 95% CI -0.05 to 0.08; 2 studies, 396 infants; low-certainty evidence). Only one study enrolling 79 infants reported components of the outcome moderate to severe neurodevelopmental disability at 18 to 26 months. The evidence is very uncertain about the effect of caffeine on cognitive developmental delay compared to other methylxanthines (RR 0.17, 95% CI 0.02 to 1.37; RD -0.12, 95% CI -0.24 to 0.01; 1 study, 79 infants; very low-certainty evidence). The evidence is very uncertain about the effect of caffeine on language developmental delay compared to other methylxanthines (RR 0.76, 95% CI 0.37 to 1.58; RD -0.07, 95% CI -0.27 to 0.12; 1 study, 79 infants; very low-certainty evidence). The evidence is very uncertain about the effect of caffeine on motor developmental delay compared to other methylxanthines (RR 0.50, 95% CI 0.13 to 1.96; RD -0.07, 95% CI -0.21 to 0.07; 1 study, 79 infants; very low-certainty evidence). The evidence is very uncertain about the effect of caffeine on visual and hearing impairment compared to other methylxanthines. At 24 months of age, visual impairment was seen in 8 out of 11 infants and 10 out of 11 infants in the caffeine and other methylxanthines groups, respectively. Hearing impairment was seen in 2 out of 5 infants and 1 out of 1 infant in the caffeine and other methylxanthines groups, respectively. No studies reported the outcomes cerebral palsy, gross motor disability, and mental development. Compared to other methylxanthines, caffeine may result in little to no difference in BPD/chronic lung disease, defined as 28 days of oxygen exposure at 36 weeks' postmenstrual age (RR 1.40, 95% CI 0.92 to 2.11; RD 0.04, 95% CI -0.01 to 0.09; 3 studies, 481 infants; low-certainty evidence). The evidence is very uncertain about the effect of caffeine on side effects (tachycardia, agitation, or feed intolerance) leading to a reduction in dose or withholding of methylxanthines compared to other methylxanthines (RR 0.17, 95% CI 0.02 to 1.32; RD -0.29, 95% CI -0.57 to -0.02; 1 study, 30 infants; very low-certainty evidence). Caffeine may result in little to no difference in duration of hospital stay compared to other methylxanthines (median (interquartile range): caffeine 43 days (27.5 to 61.5); other methylxanthines 39 days (28 to 55)). No studies reported the outcome seizures.

AUTHORS' CONCLUSIONS

Although caffeine has been shown to improve important clinical outcomes, in the few studies that compared caffeine to other methylxanthines, there might be little to no difference in mortality, bronchopulmonary dysplasia, and duration of hospital stay. The evidence is very uncertain about the effect of caffeine compared to other methylxanthines on long-term development and side effects. Although caffeine or other methylxanthines are widely used in preterm infants, there is little direct evidence to support the choice of which methylxanthine to use. More research is needed, especially on extremely preterm infants born before 28 weeks of gestation. Data from four ongoing studies might provide more evidence on the effects of caffeine or other methylxanthines.

Evaluation of the Congenital Hypothyroidism Detection Strategy in Extremely Preterm Infants in Western Andalusia

OBJECTIVE

This study aimed to identify extremely premature infants (< 31 weeks of gestation and/or <1,500 g) affected by congenital hypothyroidism (CH) with delayed elevation of thyrotropin (TSH) and to evaluate the detection strategy for this pathology in our reference screening population.

STUDY DESIGN

A descriptive and retrospective study was carried out with samples collected from western Andalusia and the autonomous city of Ceuta.

RESULTS

This protocol allowed us to detect six neonates with delayed TSH elevation. One of them, due to serious heart problems, died without being able to confirm CH. In two neonates, however, it was possible to detect CH, another two presented a persistent TSH elevation but normal free T4, and another one presented a temporary TSH elevation.

CONCLUSION

It is essential to repeat the CH screening in extremely premature infants, not only at the age of 15 days but also with a third sample at the moment of hospital discharge to detect cases with delayed TSH elevation.

KEY POINTS

· The Newborn Screening Programs are an essential activity of preventive medicine.. · Extremely preterm infants have a very high risk of CH.. · Optimal management of thyroid dysfunction in this population remains to be established..

Ataxia Rating Scales Reveal Increased Scores in Very Preterm Born 5-6-Year-Old Preschool Children and Young Adults

The aim of this study is to investigate whether scores in ataxia rating scales (ARS) are different in very preterm (VP) preschool and adult participants compared to term controls. This is a case-control study. Sixty VP children (years: 5.5-6.5; gestational age: 23.9-31.7 weeks) and 56 VP adults (years: 17.8-27.9; gestational age: 23.3-32.0 weeks) without major cerebral lesions participated in the study; 60-age and sex-matched term children and 64 term adults for comparison were used in the study intervened with the assessment with International Cooperative Ataxia Rating Scale (ICARS) and Scale for Assessment and Rating of Ataxia (SARA). Main outcome measures are primary outcome: total icars and sara scores in preterm (vp) participants versus controls. Results showed that VP children showed significantly higher total ICARS (M 15.98, SD 6.29, range 4.0-32.0; p < .001) and SARA scores (M 6.5, SD 2.53, range 1.0-15.0; p < .001) than controls (ICARS: M 9.17, SD 3.88, range 2.0-20.0; SARA: M 3.51, SD 1.54, range 1.0-8.0). VP adults also showed significantly higher total ICARS (M 1.0, SD 1.99, range 0.0-11.0; p < .001) and SARA scores (M 0.54, SD 1.08, range 0.0-6.0; p < .001) than controls (ICARS: M 0.11, SD 0.44, range 0.0-2.0; SARA: M 0.04, SD 0.18, range 0.0-1.0). In conclusion, VP children showed significantly higher scores in ARS than controls. These differences were also present in VP adults, suggesting that deficits likely prevail until adulthood. ARS are a time and cost-effective method to screen for difficulties in coordination and balance in a patient group at risk.

Traffic-related air pollution is associated with spontaneous extremely preterm birth and other adverse perinatal outcomes

BACKGROUND

Although there is growing awareness of the relationship between air pollution and preterm birth, limited data exist regarding the relationship with spontaneous preterm birth and severe neonatal outcomes.

OBJECTIVE

This study aimed to examine the association between traffic-associated air pollution exposure in pregnancy and adverse perinatal outcomes including extremes of preterm birth, neonatal intensive care unit admissions, low birthweight, neonatal respiratory diagnosis, neonatal respiratory support, and neonatal sepsis evaluation.

STUDY DESIGN

This was a retrospective cohort study of singleton pregnancies of patients residing in a metropolitan area in the southern United States. Using monitors strategically located across the region, average nitrogen dioxide concentrations were obtained from the Environmental Protection Agency Air Quality System database. For patients living within 10 miles of a monitoring station, average exposure to nitrogen dioxide was estimated for individual patients' pregnancy by trimester. Logistic regression models were used to assess the effect of pollutant exposure on gestational age at birth, indicated vs spontaneous delivery, and neonatal outcomes while adjusting for maternal age, self-reported race, parity, season of conception, diabetes mellitus, body mass index, registered Health Equity Index, and nitrogen dioxide monitor region. Adjusted odds ratios and 95% confidence intervals were calculated for an interquartile increase in average nitrogen dioxide exposure.

RESULTS

Between January 1, 2013 and December 31, 2021, 93,164 patients delivered a singleton infant. Of these, 62,189 had measured nitrogen dioxide exposure during the pregnancy from a nearby monitoring station. Higher average nitrogen dioxide exposure throughout pregnancy was significantly associated with preterm birth (adjusted odds ratio, 1.94; 95% confidence interval, 1.77-2.12) and an increase in neonatal intensive care unit admissions, low birthweight infants, neonatal respiratory diagnosis, neonatal respiratory support, and neonatal sepsis evaluation. This relationship persisted for nulliparous patients and spontaneous preterm birth, and had a greater association with earlier preterm birth.

CONCLUSION

In a metropolitan area, increased exposure to the air pollutant nitrogen dioxide in pregnancy was associated with spontaneous preterm birth and had a greater association with extremely preterm birth. A greater association with neonatal intensive care unit admissions, low-birthweight infants, neonatal respiratory diagnosis, neonatal respiratory support, and neonatal sepsis evaluation was found even in term infants.

Trends in Gestational Age-Related Intelligence Outcomes of School-Age Children Born Very Preterm from 2001 to 2015 in Taiwan

OBJECTIVE

To investigate whether gestational age (GA)-related intelligence outcomes of children born very preterm improved over time.

STUDY DESIGN

A multicenter cohort study recruited 4717 infants born at GA <31 weeks and admitted to neonatal intensive care units between 2001 and 2015 in Taiwan. Intelligence outcomes at age 5.5 years were classified by intelligent quotient (IQ) into no cognitive impairment (IQ > -1 SD), mild cognitive impairment (IQ = -1∼-2 SD), and moderate/severe cognitive impairment (IQ < -2 SD). Trends were assessed for neonatal morbidities, mortality, and intelligence outcomes by birth epoch (2001-2003, 2004-2006, 2007-2009, 2010-2012, 2013-2015) and GA (23-24, 25-26, 27-28, 29-30 weeks).

RESULTS

Maternal education levels increased and rates of brain injury and mortality decreased over time. Among the 2606 children who received IQ tests, the rates of no, mild, and moderate/severe cognitive impairment were 54.5%, 30.5%, and 15.0%, respectively. There were significant trends in the increasing rates of no cognitive impairment and declining rates of mild and moderate/severe cognitive impairment in all GA groups across the 5 birth epochs. Relative to the occurrence in 2001-2003, the odds were significantly reduced for moderate/severe cognitive impairment from 2007-2009 (aOR 0.49, 95% CI 0.30-0.81) to 2013-2015 (0.35, 0.21-0.56) and for mild cognitive impairment from 2010-2012 (0.54, 0.36-0.79) to 2013-2015 (0.36, 0.24-0.53).

CONCLUSIONS

For children born very preterm between 2001 and 2015 in Taiwan, the improvement of maternal education levels and improvements in neonatal brain injury and mortality were temporally associated with trends of decreasing intellectual impairment at school age across all GA groups.

Sustained lower bilirubin-binding affinity of albumin in extremely preterm infants

BACKGROUND

Elevated albumin-free or unbound bilirubin (UB) levels beyond the first week of life have been associated with the development of bilirubin encephalopathy in preterm infants. However, the mechanism(s) that induces this prolonged unbound bilirubinemia has remained unknown. We hypothesized that it may due to a sustained lower bilirubin-binding affinity of albumin in extremely premature infants.

METHODS

Twenty-two very preterm infants born at 28-31 weeks' gestational age (GA) (VPT Group) and 21 extremely preterm infants born at 22-27 weeks' GA (EPT Group) were retrospectively studied. On days 14, 21, and 28, bilirubin-binding affinity of albumin was assessed by calculating of the UB/total bilirubin ratio, bilirubin-albumin molar ratio (BAMR), and binding affinity (Ka).

RESULTS

On days 14, 21, and 28, significantly higher UB/total bilirubin ratios were found in the EPT than in the VPT Group. Although BAMRs were comparable, significantly lower Ka values on days 14, 21, and 28 were observed in the EPT than those in the VPT Group (56.1 vs. 70.9 L/μmol, p < 0.001; 55.2 vs. 74.7 L/μmol, p < 0.001; 53.0 vs. 86.5 L/μmol, p < 0.001, respectively).

CONCLUSIONS

EPT infants have a sustained lower bilirubin-binding affinity of albumin beyond the first week of life.

IMPACT

Bilirubin encephalopathy is still reported in extremely preterm (EPT) infants. EPT infants often have prolonged unbound bilirubinemia beyond the first week of life. Sustained lower bilirubin-binding affinity of albumin, regardless of the bilirubin-albumin molar ratio (BAMR), is observed in EPT infants. BAMRs should not be used as a surrogate marker of unbound bilirubinemia, especially in EPT infants at a later postnatal period.

Optimal timing of extubation in preterm infants

In neonatal intensive care, endotracheal intubation is usually performed as an urgent or semi-urgent procedure in infants with critical or unstable conditions related to progressive respiratory failure. Extubation is not. Patients undergoing extubation are typically stable, with improved respiratory function. The key elements to facilitating extubation are to recognize improvement in respiratory status, promote weaning of mechanical ventilation, and accurately identify readiness for removal of the endotracheal tube. Therefore, extubation should be a planned and well-organized procedure. In this review, we will appraise the evidence for existing predictors of extubation readiness and provide patient-specific, pathophysiology-derived strategies to optimize the timing and success of extubation in neonates, with a focus on extremely preterm infants.

Bayley trajectories predict school readiness better than single assessments in formerly very preterm preschoolers

BACKGROUND

Development of children born very preterm (VPT) is evaluated using the Bayley Scales of Infant Development. Early Bayley scores may not predict later outcomes. We studied whether VPT Bayley trajectories in the early years predicted school readiness better than single assessments.

METHODS

We prospectively evaluated 53 VPT at 4-5 years using standardized measures of school readiness, including the domains of cognition, early mathematical and literacy abilities, and motor skills. Predictors were Bayley-III scores obtained 1-5 times/child between 6 and 35 months. Linear mixed models (LMM) with random effects extracted estimated random effect for slope (change in Bayley score/1 year) and fixed+random effect sum for the intercept (initial Bayley score) for each participant, to then evaluate 4-5-year outcomes prediction.

RESULTS

Variability of individual trajectories prevailed across developmental domains. For the initial LMM, adding Bayley change to models with only initial score improved model fits for several Bayley-III domains. Models containing estimates for initial Bayley scores and Bayley change explained significantly more variability in school readiness scores (21-63%) than either variable alone.

CONCLUSION

Neurodevelopmental follow-up of VPT is more relevant to school readiness when children are assessed multiple times in the first 3 years. Neonatal intervention research could use early trajectories rather than single timepoints as outcomes.

IMPACT

This study is the first to examine individual Bayley scores and trajectories to predict school readiness of formerly preterm children at 4-5 years. Modeling demonstrated extreme variability of individual trajectories compared to the group's average trajectories. Models containing initial Bayley scores and Bayley change over time explained more variability in preschool readiness than either variable alone. Using the Bayley to predict future school readiness is enhanced by administration across multiple follow-up visits and inclusion of change across the first 3 years. Follow-up care models and clinical trial design for neonatal interventions may benefit from a trajectory-based approach to outcomes evaluation.

Early life surfactant protein-D levels in bronchoalveolar lavage fluids of extremely preterm neonates

Surfactant protein-D (SP-D) is a hydrophilic protein with multiple crucial anti-inflammatory and immunological functions. It might play a role in the development and course of pulmonary infections, acute respiratory distress syndrome, and other respiratory disorders. Only few small neonatal studies have investigated SP-D: we aimed to investigate the links between this protein, measured in the first hours of life in extremely preterm neonates, and clinical outcomes, as well its relationship with pulmonary secretory phospholipase A2 (sPLA2). Bronchoalveolar lavage fluids were obtained within the first 3 h of life. SP-D and sPLA2 were measured with ELISA and radioactive method, respectively; epithelial lining fluid concentrations were estimated with urea ratio. Clinical data were prospectively collected. One hundred extremely preterm neonates were nonconsecutively studied. SP-D was significantly raised with increasing gestational age (24-26 wk: 68 [0-1,694], 27 or 28 wk: 286 [0-1,328], 29 or 30 wk: 1,401 [405-2,429] ng/mL, overall P = 0.03). SP-D was significantly higher in cases with clinical chorioamnionitis with fetal involvement (1,138 [68-3,336]) than in those without clinical chorioamnionitis with fetal involvement (0 [0-900] ng/mL, P < 0.001). SP-D was lower in infants with bronchopulmonary dysplasia (BPD) (251 [0-1,550 ng/mL]) compared with those without bronchopulmonary dysplasia (BPD) or who died before its diagnosis (977 [124-5,534 ng/mL], P = 0.05) and this was also significant upon multivariate analysis [odds ration (OR): 0.997 (0.994-0.999), P = 0.024], particularly in neonates between 27- and 28-wk gestation. SP-D significantly correlated with the duration of hospital stay (ρ = -0.283, P = 0.002), invasive ventilation (ρ = -0.544, P = 0.001), and total sPLA2 activity (ρ = 0.528, P = 0.008). These findings help understanding the role of SP-D early in life and support further investigation about the role of SP-D in developing BPD.NEW & NOTEWORTHY Surfactant protein-D increases with gestational age and is inversely associated with BPD development. These results have been obtained in the first hours of life of extremely preterm neonates with optimal perinatal care.

Acetaminophen for the patent ductus arteriosus: has safety been adequately demonstrated?

Patent ductus arteriosus (PDA) is the most common cardiovascular condition diagnosed in premature infants. Acetaminophen was first proposed as a potential treatment for PDA in 2011. Since that time acetaminophen use among extremely preterm neonates has increased substantially. The limited available data demonstrate that acetaminophen reduces PDA without evident hepatotoxicity. These findings have led some to suggest that acetaminophen is a safe and effective therapy for PDA closure. However, the lack of apparent hepatoxicity is predictable. Acetaminophen induced cellular injury is due to CYP2E1 derived metabolites; and hepatocyte CYP2E1 expression is low in the fetal and neonatal period. Here, we review preclinical and clinical data that support the hypothesis that the lung, which expresses high levels of CYP2E1 during fetal and early postnatal development, may be particularly susceptible to acetaminophen induced toxicity. Despite these emerging data, the true potential pulmonary risks and benefits of acetaminophen for PDA closure are largely unknown. The available clinical studies in are marked by significant weakness including low sample sizes and minimal evaluation of extremely preterm infants who are typically at highest risk of pulmonary morbidity. We propose that studies interrogating mechanisms linking developmentally regulated, cell-specific CYP2E1 expression and acetaminophen-induced toxicity as well as robust assessment of pulmonary outcomes in large trials that evaluate the safety and efficacy of acetaminophen in extremely preterm infants are needed.

Circumstances, causes and timing of death in extremely preterm infants admitted to NICU: The EPIPAGE-2 study

AIM

To describe the circumstances, causes and timing of death in extremely preterm infants.

METHODS

We included from the EPIPAGE-2 study infants born at 24-26 weeks in 2011 admitted to neonatal intensive care units (NICU). Vital status and circumstances of death were used to define three groups of infants: alive at discharge, death with or without withholding or withdrawing life-sustaining treatment (WWLST). The main cause of death was classified as respiratory disease, necrotizing enterocolitis, infection, central nervous system (CNS) injury, other or unknown.

RESULTS

Among 768 infants admitted to NICU, 224 died among which 89 died without WWLST and 135 with WWLST. The main causes of death were respiratory disease (38%), CNS injury (30%) and infection (12%). Among the infants who died with WWLST, CNS injury was the main cause of death (47%), whereas respiratory disease (56%) and infection (20%) were the main causes in case of death without WWLST. Half (51%) of all deaths occurred within the first 7 days of life, and 35% occurred within 8 and 28 days.

CONCLUSION

The death of extremely preterm infants in NICU is a complex phenomenon in which the circumstances and causes of death are intertwined.

Artificial placenta technology: History, potential and perception

As presently conceptualised, the artificial placenta (AP) is an experimental life support platform for extremely preterm infants (i.e. 400-600 g; 21-23+6 weeks of gestation) born at the border of viability. It is based around the oxygenation of the periviable fetus using gas-exchangers connected to the fetal vasculature. In this system, the lung remains fluid-filled and the fetus remains in a quiescent state. The AP has been in development for some sixty years. Over this time, animal experimental models have evolved iteratively from employing external pump-driven systems used to support comparatively mature fetuses (generally goats or sheep) to platforms driven by the fetal heart and used successfully to maintain extremely premature fetuses weighing around 600 g. Simultaneously, sizable advances in neonatal and obstetric care mean that the nature of a potential candidate patient for this therapy, and thus the threshold success level for justifying its adoption, have both changed markedly since this approach was first conceived. Five landmark breakthroughs have occurred over the developmental history of the AP: i) the first human studies reported in the 1950's; ii) foundation animal studies reported in the 1960's; iii) the first extended use of AP technology combined with fetal pulmonary resuscitation reported in the 1990s; iv) the development of AP systems powered by the fetal heart reported in the 2000's; and v) the adaption of this technology to maintain extremely preterm fetuses (i.e. 500-600 g body weight) reported in the 2010's. Using this framework, the present paper will provide a review of the developmental history of this long-running experimental system and up-to-date assessment of the published field today. With the apparent acceleration of AP technology towards clinical application, there has been an increase in the attention paid to the field, along with some inaccurate commentary regarding its potential application and merits. Additionally, this paper will address several misrepresentations regarding the potential application of AP technology that serve to distract from the significant potential of this approach to greatly improve outcomes for extremely preterm infants born at or close to the present border of viability.

Correlation of NICU anthropometry in extremely preterm infants with brain development and language scores at early school age

Growth in preterm infants in the neonatal intensive care unit (NICU) is associated with increased global and regional brain volumes at term, and increased postnatal linear growth is associated with higher language scores at age 2. It is unknown whether these relationships persist to school age or if an association between growth and cortical metrics exists. Using regression analyses, we investigated relationships between the growth of 42 children born extremely preterm (< 28 weeks gestation) from their NICU hospitalization, standardized neurodevelopmental/language assessments at 2 and 4-6 years, and multiple neuroimaging biomarkers obtained from T1-weighted images at 4-6 years. We found length at birth and 36 weeks post-menstrual age had positive associations with language scores at 2 years in multivariable linear regression. No growth metric correlated with 4-6 year assessments. Weight and head circumference at 36 weeks post-menstrual age positively correlated with total brain volume and negatively with global cortical thickness at 4-6 years of age. Head circumference relationships remained significant after adjusting for age, sex, and socioeconomic status. Right temporal cortical thickness was related to receptive language at 4-6 years in the multivariable model. Results suggest growth in the NICU may have lasting effects on brain development in extremely preterm children.

Delivery room intubation and severe intraventricular hemorrhage in extremely preterm infants without low Apgar scores: A Japanese retrospective cohort study

The purpose of this study was to assess the associations between delivery room intubation (DRI) and severe intraventricular hemorrhage (IVH), as well as other neonatal outcomes, among extremely preterm infants without low Apgar scores using data from a large-scale neonatal registry data in Japan. We analyzed data for infants born at 24-27 gestational weeks between 2003 and 2019 in Japan using robust Poisson regression. Infants with low Apgar scores (≤ 1 at 1 min or ≤ 3 at 5 min) were excluded. The primary outcome was severe IVH. Secondary outcomes were other neonatal morbidities and mortality. The full cohort included 16,081 infants (intubation cohort, 13,367; no intubation cohort, 2714). The rate of DRI increased over time (78.6%, 2003-2008; 83.4%, 2009-2014; 87.8%, 2015-2019), while the rate of severe IVH decreased (7.1%, 2003-2008; 5.7%, 2009-2014; 5.3%, 2015-2019). Infants with DRI had a higher risk of severe IVH than those without DRI (6.8% vs. 2.3%; adjusted risk ratio, 1.86; 95% confidence interval, 1.33-2.58). The results did not change substantially when stratified by gestational age. Despite conflicting changes over time in DRI and severe IVH, DRI was associated with an increased risk of severe IVH among extremely preterm infants in Japan.

Oxygen saturation levels and retinopathy of prematurity in extremely preterm infants - a case control study

PURPOSE

To investigate the association of risk factors, including oxygen exposure, for developing retinopathy of prematurity (ROP) in preterm infants at increased risk of ROP.

METHODS

A case-control study was conducted where each infant born at < 28 weeks gestation with ROP was matched with another without ROP over five years (July 2015 - June 2020). Clinical information about the infants was collected from electronic medical records, including method of oxygen delivery, oxygen saturation (SpO2), fraction of inspired oxygen (FiO2) and mean airway pressure (MAP) measurements. MATLAB was used for a time-averaged analysis. Stata/SE 16.0 was used for statistical analysis.

RESULTS

123 ROP/non-ROP pairs were included in this study. The time-averaged SpO2 analysis showed non-ROP group spent more time in hyperoxia than the ROP group (p < 0.001). The non-ROP group had lower respiratory severity scores and analysis when FiO2 > 21% showed that were was no difference in SpO2 between the two groups when the infants were receiving oxygen support. Conditional logistic regressions showed neonatal surgery significantly increased the risk of ROP (OR = 1.4347, p = 0.010), while the influence of birthweight (odds ratio of 0.9965, p = 0.001) and oxygen exposure (OR = 0.9983, p = 0.012) on ROP outcome was found to be negligible as their odds ratios indicated no influence.

CONCLUSIONS

At times when infants were receiving respiratory support (FiO2 > 21%) the SpO2 data indicated no difference in SpO2 between the ROP and non-ROP groups. Analysis of clinical variables found that neonatal surgery increased the odds of developing ROP.

Cognitive Training for Visuospatial Processing in Children Aged 5½ to 6 Years Born Very Preterm With Working Memory Dysfunction: A Randomized Clinical Trial

Importance

Compared with term-born peers, children born very preterm generally perform poorly in executive functions, particularly in working memory and inhibition. By taking advantage of neuroplasticity, computerized cognitive training of working memory in those children could improve visuospatial processing by boosting visual inhibition via working memory.

Objective

To evaluate the long-term effect of cognitive working memory training on visuospatial processing in children aged 5½ to 6 years born very preterm who have working memory impairment.

Design, Setting, and Participants

This multicenter (18 French university hospitals), open-label randomized clinical trial with 2 parallel groups (EPIREMED) was conducted from November 2016 to April 2018, with the last follow-up during August 2019. Eligible children from the EPIPAGE 2 cohort were aged 5½ to 6 years, were born between 24 and 34 weeks' gestation, and had a global intelligence quotient greater than 70 and a working memory index less than 85. Data were analyzed from February to December 2020.

Intervention

Children were randomized 1:1 to standard care management and a working memory cognitive training program (Cogmed software) for 8 weeks (25 sessions) (intervention) or to standard management (control).

Main Outcomes and Measures

The primary outcome was the visuospatial index score from the Wechsler Preschool and Primary Scale of Intelligence, 4th Edition. Secondary outcomes were working memory, intellectual functioning, executive and attention processes, language skills, behavior, quality of life, and schooling. Neurobehavioral assessments were performed at inclusion and after finishing training at 6 months (intermeditate assessment; secondary outcomes) and at 16 months (final assessment; primary outcome).

Results

There were 169 children randomized, with a mean (SD) age of 5 years 11 months (2 months); 91 (54%) were female. Of the participants, 84 were in the intervention group (57 of whom [68%] completed at least 15 cognitive training sessions) and 85 were in the control group. The posttraining visuospatial index score was not different between groups at a mean (SD) of 3.0 (1.8) months (difference, -0.6 points; 95% CI, -4.7 to 3.5 points) or 12.9 (2.6) months (difference, 0.1 points; 95% CI, -5.4 to 5.1 points). The working memory index score in the intervention group significantly improved from baseline at the intermediate time point (difference, 4.7 points; 95% CI, 1.2-8.1 points), but this improvement was not maintained at the final assessment.

Conclusions and Relevance

This randomized clinical trial found no lasting effect of a cognitive training program on visuospatial processing in children aged 5½ to 6 years with working memory disorders who were born very preterm. The findings suggest that this training has limited long-term benefits for improving executive function. Transient benefits seemed to be associated with the developmental state of executive functions.

Trial Registration

ClinicalTrials.gov Identifier: NCT02757794.

Apgar Score and Neurodevelopmental Outcomes at Age 5 Years in Infants Born Extremely Preterm

Importance

The Apgar score is used worldwide as an assessment tool to estimate the vitality of newborns in their first minutes of life. Its applicability to estimate neurodevelopmental outcomes in infants born extremely preterm (EPT; <28 weeks' gestation) is not well established.

Objective

To investigate the association between the Apgar score and neurodevelopmental outcomes in infants born EPT.

Design, Setting, and Participants

This cohort study was conducted using data from the Effective Perinatal Intensive Care in Europe-Screening to Improve Health in Very Preterm Infants in Europe (EPICE-SHIPS) study, a population-based cohort in 19 regions of 11 European countries in 2011 to 2012. Clinical assessments of cognition and motor function at age 5 years were performed in infants born EPT and analyzed in January to July 2023.

Exposures

Apgar score at 5 minutes of life categorized into 4 groups (0-3, 4-6, 7-8, and 9-10 points).

Main Outcomes and Measures

Cognitive and motor outcomes were assessed using the Wechsler Preschool and Primary Scale of Intelligence test of IQ derived from locally normed versions by country and the Movement Assessment Battery for Children-Second Edition. Parents additionally provided information on communication and problem-solving skills using the Ages and Stages Questionnaire, third edition (ASQ-3). All outcomes were measured as continuous variables.

Results

From the total cohort of 4395 infants born EPT, 2522 infants were live born, 1654 infants survived to age 5 years, and 996 infants (478 females [48.0%]) followed up had at least 1 of 3 outcome measures. After adjusting for sociodemographic variables, perinatal factors, and severe neonatal morbidities, there was no association of Apgar score with IQ, even for scores of 3 or less (β = -3.3; 95% CI, -10.5 to 3.8) compared with the score 9 to 10 category. Similarly, no association was found for ASQ-3 (β = -2.1; 95% CI, -24.6 to 20.4). Congruent results for Apgar scores of 3 or less were obtained for motor function scores for all children (β = -4.0; 95% CI, -20.1 to 12.1) and excluding children with a diagnosis of cerebral palsy (β = 0.8, 95% CI -11.7 to 13.3).

Conclusions and Relevance

This study found that low Apgar scores were not associated with longer-term outcomes in infants born EPT. This finding may be associated with high interobserver variability in Apgar scoring, reduced vitality signs and poorer responses to resuscitation after birth among infants born EPT, and the association of more deleterious exposures in the neonatal intensive care unit or of socioeconomic factors with greater changes in outcomes during the first 5 years of life.

Late-onset sepsis in very preterm infants in Norway in 2009-2018: a population-based study

OBJECTIVE

To evaluate epidemiology and outcomes among very preterm infants (<32 weeks' gestation) with culture-positive and culture-negative late-onset sepsis (LOS).

DESIGN

Cohort study using a nationwide, population-based registry.

SETTING

21 neonatal units in Norway.

PARTICIPANTS

All very preterm infants born 1 January 2009-31 December 2018 and admitted to a neonatal unit.

MAIN OUTCOME MEASURES

Incidences, pathogen distribution, LOS-attributable mortality and associated morbidity at discharge.

RESULTS

Among 5296 very preterm infants, we identified 582 culture-positive LOS episodes in 493 infants (incidence 9.3%) and 282 culture-negative LOS episodes in 282 infants (incidence 5.3%). Extremely preterm infants (<28 weeks' gestation) had highest incidences of culture-positive (21.6%) and culture-negative (11.1%) LOS. The major causative pathogens were coagulase-negative staphylococci (49%), Staphylococcus aureus (15%), group B streptococci (10%) and Escherichia coli (8%). We observed increased odds of severe bronchopulmonary dysplasia (BPD) associated with both culture-positive (adjusted OR (aOR) 1.7; 95% CI 1.3 to 2.2) and culture-negative (aOR 1.6; 95% CI 1.3 to 2.6) LOS. Only culture-positive LOS was associated with increased odds of cystic periventricular leukomalacia (cPVL) (aOR 2.2; 95% CI 1.4 to 3.4) and severe retinopathy of prematurity (ROP) (aOR 1.8; 95% CI 1.2 to 2.8). Culture-positive LOS-attributable mortality was 6.3%, higher in Gram-negative (15.8%) compared with Gram-positive (4.1%) LOS, p=0.009. Among extremely preterm infants, survival rates increased from 75.2% in 2009-2013 to 81.0% in 2014-2018, p=0.005. In the same period culture-positive LOS rates increased from 17.1% to 25.6%, p<0.001.

CONCLUSIONS

LOS contributes to a significant burden of disease in very preterm infants and is associated with increased odds of severe BPD, cPVL and severe ROP.

Changes in preterm and extremely preterm birth rates in Japan after the introduction of obstetrical practice guidelines in 2008

AIM

Obstetrical guidelines were established in Japan in 2008, and obstetrical diagnoses and treatments were subsequently standardized nationally. We examined changes in the preterm birth rate (PTBR) and extremely preterm birth rate (EPTBR) following the introduction of such guidelines.

METHODS

Information on 50 706 432 live births in Japan between 1979 and 2021, including Japanese reproductive medicine, the childbearing age of pregnant women, and the employment status of reproductive-age women between 2007 and 2020, were obtained from the Japanese government and academic societies. Regression analysis was used to compare chronological changes nationally and those of eight Japanese regions. Regional and national average PTBRs and EPTBRs from 2007 to 2020 were compared by using a repeated measures analysis of variance.

RESULTS

From 1979 to 2007, PTBRs and EPTBRs in Japan increased significantly. However, from 2008, the national PTBR and EPTBR decreased until 2020 (p < 0.001) and 2019 (p = 0.02), respectively. From 2007 to 2020, overall PTBR and EPTBR were 5.68% and 0.255%, respectively. A significant difference in the PTBR and EPTBR existed between the eight Japanese regions. During this period, the number of pregnancies using assisted reproductive technology increased from 19 595 to 60 381, pregnant women became older, the employment rate of those of reproductive age increased, and nonregular employment was 54%, which was 2.5 times higher than for men.

CONCLUSIONS

In Japan, after obstetrical guidelines were enacted in 2008, PTRBs decreased significantly even under the pressure of increasing preterm births. Countermeasures may be necessary for regions showing high PTBRs.

Early Human Milk Fortification in Infants Born Extremely Preterm: A Randomized Trial

OBJECTIVES

Enteral nutrition with unfortified human milk during the first 2 postnatal weeks often leads to cumulative protein and energy deficits among preterm infants. Fortified human milk administered soon after birth could increase fat-free mass (FFM) and improve growth in these infants.

METHODS

This was a masked, randomized trial. Starting on feeding day 2, extremely preterm infants 28 weeks or younger fed maternal or donor milk were randomized to receive either a diet fortified with a human-based product (intervention group) or a standard, unfortified diet (control group). This practice continued until the feeding day when a standard bovine-based fortifier was ordered. Caregivers were masked. The primary outcome was FFM-for-age z score at 36 weeks of postmenstrual age (PMA).

RESULTS

A total of 150 infants were randomized between 2020 and 2022. The mean birth weight was 795±250 g, and the median gestational age was 26 weeks. Eleven infants died during the observation period. The primary outcome was assessed in 105 infants (70%). FFM-for-age z scores did not differ between groups. Length gain velocities from birth to 36 weeks PMA were higher in the intervention group. Declines in head circumference-for-age z score from birth to 36 weeks' PMA were less pronounced in the intervention group.

CONCLUSIONS

In infants born extremely preterm, human milk diets fortified soon after birth do not increase FFM accretion at 36 weeks' PMA, but they may increase length gain velocity and reduce declines in head circumference-for-age z scores from birth to 36 weeks' PMA.

Dilemmas in the delivery of intravenous lipid emulsions and approach to hypertriglyceridemia in very preterm and low birth weight infants

Intravenous lipid emulsions (ILEs) are an essential component of parenteral nutrition for very preterm and very low birth weight infants (VLBWs). This article offers a perspective on advancements and controversies on ILE use in this population. ILEs prescribed after birth at a dose of 1.5-2 g/kg/day and advanced to 3 g/kg/day enhance growth. Growth appears to be similar for infants who receive an ILE composed of 100% soybean oil or a multi-oil ILE with 15% fish oil. 100% fish oil is the preferred ILE for the management of parenteral nutrition associated cholestasis and intestinal failure associated liver disease. Research is warranted to help determine how we can optimize ILEs to improve neurodevelopment and prematurity complications. Last, we lack a universal definition of hypertriglyceridemia (HTG) and consensus on triglyceride surveillance and HTG management. Investigation is required to determine the health impact of specific triglyceride ranges in very preterm infants and VLBWs.

Fluid Intake in the First Week of Life and the Duration of Hemodynamically Significant Patent Ductus Arteriosus in Extremely Preterm Infants

OBJECTIVE

This study aimed to determine the association between daily fluid intake and the duration of hemodynamically significant patent ductus arteriosus (hsPDA).

STUDY DESIGN

This is a retrospective cohort study of extremely preterm infants (<29 weeks) admitted in the Neonatal Intensive Care Unit of the Advent Health for Children from January 2013 to March 2016, if hsPDA was diagnosed in first week of life and serial echocardiograms were available. Diagnosis of hsPDA was based on a scoring system and its duration was estimated from serial echocardiograms. Cohort was divided into two groups based on duration of hsPDA (<1week, group A and ≥1 week, group B). Daily fluid intake was categorized as prescribed and actual. Prescribed volume was ordered by clinicians based on birth weight, not including trophic feeds, intravenous (IV) boluses or transfusions, etc. Actual intake was calculated by the electronic medical records based on daily weights and included all enteral or parenteral fluids. Multivariate analysis was performed to determine an association between total daily fluid intake over the first week of life and the duration of hsPDA. Two groups were compared to observe the difference between prescribed and actual daily fluid intakes.

RESULTS

We enrolled 50 infants in group A and 76 in group B. Infants in group B were of significantly lower gestation and required prolonged ventilation and hospitalization. An association between higher fluid intake in the first 2 days of life and prolonged duration of hsPDA was confirmed by multivariate analysis. Actual fluid intake was significantly higher than prescribed total fluid intake in first 4 days of life for infants in both groups.

CONCLUSION

In extremely preterm infants, higher fluid intake in first 2 days of life is associated with prolonged duration of hsPDA. Actual daily fluid intake can be significantly higher than prescribed daily fluids due to daily weight changes and additional fluid administration.

KEY POINTS

· In preterm infants, actual daily fluid intake may be higher than prescribed volume.. · Higher daily fluid intake in first week of life is associated with prolonged duration of PDA.. · PDA scoring system can be helpful for objective assessment of PDA in preterm infants..

Neurobehavioral and Medical Correlates of Autism Screening: 2-Year Outcomes for Infants Born Very Preterm

OBJECTIVE

To identify neonatal characteristics and 2-year neurodevelopmental outcomes associated with positive screening for risk of autism.

STUDY DESIGN

Nine university-affiliated neonatal intensive care units (NICUs) enrolled infants born at <30 weeks of gestation. Infants underwent the NICU Network Neurobehavioral Scale examination before discharge and the Bayley Scales of Infant and Toddler Development, Third Edition, the Child Behavior Checklist, and the Modified Checklist for Autism in Toddlers, revised with follow-up (M-CHAT-R/F) at 2 years of corrected age. Generalized estimating equations examined associations between M-CHAT-R/F, neurobehavioral test results, and neonatal medical morbidities.

RESULTS

At 2 years of corrected age, data were available for 466 of 744 enrolled infants without cerebral palsy. Infants with hypoaroused NICU Network Neurobehavioral Scale profiles were more likely to screen M-CHAT-R/F-positive (OR 2.76, 95% CI 1.38-5.54). Infants with ≥2 medical morbidities also were more likely to screen positive (OR 2.65, 95% CI 1.27-5.54). Children with positive M-CHAT-R/F scores had lower Bayley Scales of Infant and Toddler Development, Third Edition, Cognitive (t [451] = 5.43, P < .001, d = 0.82), Language (t [53.49] = 7.82, P < .001, d = 1.18), and Motor (t [451] = 7.98, P < .001, d = 1.21) composite scores and significantly greater Child Behavior Checklist Internalizing (t [457] -6.19, P < .001, d = -0.93) and Externalizing (t [57.87] = -5.62, P < .001, d = -0.84) scores.

CONCLUSIONS

Positive M-CHAT-R/F screens at 2 years of corrected age were associated with neonatal medical morbidities and neurobehavioral examinations as well as toddler developmental and behavioral outcomes. These findings demonstrate the potential utility of the M-CHAT-R/F as a global developmental screener in infants born very preterm, regardless of whether there is a later autism diagnosis.

Change in neurodevelopmental outcomes for extremely premature infants over time: a systematic review and meta-analysis

OBJECTIVE

Survival rates of extremely premature infants are rising, but changes in neurodevelopmental impairment (NDI) rates are unclear. Our objective was to perform a systematic review of intrainstitutional variability of NDI over time.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Ovid MEDLINE, Embase, PubMed, Cochrane Library and Google Scholar.

STUDY SELECTION

Study eligibility: (1) at least two discrete cohorts of infants born <27 weeks' gestation or <1000 g birth weight, (2) one cohort born after 1990 and at least one subsequent cohort of similar gestational age, (3) all cohorts cared for within the same Neonatal Intensive Care Unit(s) (NICU) and (4) neurodevelopmental outcomes at 18-36 months corrected age.

MAIN OUTCOME

Change in NDI rates. Quality, validity and bias were assessed using Grading of Recommendations, Assessment, Development, and Evaluation and Quality in Prognosis Studies guidelines.

RESULTS

Of 203 publications, 15 were eligible, including 13 229 infants. At the first time point, average NDI rate across study groups weighted by sample size was 41.0% (95% CI 34.0% to 48.0%). The average change in NDI between time points was -3.3% (95% CI -8·8% to 2.2%). For each added week of gestation at birth, the rate of NDI declined by 9.7% (95% CI 6.2% to 13.3%). Most studies exhibited moderate-severe bias in at least one domain, especially attrition rates.

CONCLUSIONS

When comparing discrete same-centre cohorts over time, there was no significant change in NDI rates in infants born <27 weeks' gestation or <1000 g. Higher survival rates unaccompanied by improvement in neurodevelopment highlight urgency for renewed focus on the causes of NDI and evidence-based strategies to reduce brain injury.