Hyperbilirubinemia Among Infants Born Preterm: Peak Levels and Association with Neurodevelopmental Outcomes.

OBJECTIVE: To describe the distribution of peak bilirubin levels among infants born before 29 weeks of gestation in the first 14 days of life and to study the association between quartiles of peak bilirubin levels at different gestational ages and neurodevelopmental outcomes. STUDY DESIGN: Multicenter, retrospective, nationwide cohort study of neonatal intensive care units in the Canadian Neonatal Network and Canadian Neonatal Follow-Up Network, including neonates born preterm at 220/7 to 286/7 weeks of gestation born between 2010 and 2018. Peak bilirubin levels were recorded during the first 14 days of age. Main outcome was significant neurodevelopmental impairment, defined as cerebral palsy with Gross Motor Function Classification System ≥3, or Bayley III-IV scores of <70 in any domain, or visual impairment, or bilateral hearing loss requiring hearing aids. RESULTS: Among 12 554 included newborns, median gestational age was 26 weeks (IQR 25-28) and birth weight was 920 g (IQR 750-1105 g). The median peak bilirubin values increased as gestational age increased (112 mmol/L [6.5 mg/dL] at 22 weeks and 156 mmol/L [9.1 mg/dL] at 28 weeks). Significant neurodevelopmental impairment was identified in 1116 of 6638 (16.8%) of children. Multivariable analyses identified an association between peak bilirubin in the highest quartile and neurodevelopmental impairment (aOR 1.27, 95% CI 1.01-1.60) and receipt of hearing aid/cochlear implant (aOR 3.97, 95%CI: 2.01-7.82) compared with the lowest quartile. CONCLUSION: In this multicenter cohort study, peak bilirubin levels in neonates of <29 weeks of gestation increased with gestational age. Peak bilirubin values in the highest gestational age-specific quartile were associated with significant neurodevelopmental and hearing impairments.

Neonatal and Early Childhood Outcomes of Twin and Singleton Infants Born Preterm.

OBJECTIVE: To compare neonatal and early-childhood outcomes of twins and singletons born preterm and explore the association of chorionicity with outcomes. STUDY DESIGN: This was a national retrospective cohort study of singleton and twin infants admitted at 230/7-286/7 weeks to level III neonatal intensive care units in Canada (2010-2020). The primary neonatal outcome was a composite of neonatal death or severe neonatal morbidities. The primary early-childhood outcome was a composite of death or significant neurodevelopmental impairment. RESULTS: The study cohort included 3554 twin and 12 815 singleton infants. Twin infants born at 230/7-256/7 weeks had a greater risk of the composite neonatal outcome (adjusted risk ratio 1.04, 95% CI 1.01-1.07). However, these differences were limited to the subgroups of same-sex and monochorionic twin pregnancies. Twin infants of 230/7-256/7 weeks were also at an increased risk of the composite early-childhood outcome (adjusted risk ratio 1.22, 95% CI 1.09-1.37). Twin infants of 260/7-286/7 weeks were not at an increased risk of adverse neonatal outcomes or the composite early-childhood outcome compared with singleton infants. CONCLUSIONS: Among infants born at 230/7-256/7 weeks, twins have a greater risk of adverse neonatal outcomes and the composite early-childhood outcome than singleton infants. However, the increased risk of adverse neonatal outcomes is mostly limited to monochorionic twins and may thus be driven by complications related to monochorionic placentation.

Association of Postnatal Growth Changes and Neurodevelopmental Outcomes in Preterm Neonates of <29 Weeks' Gestation.

OBJECTIVE: To examine associations between weight and head circumference (HC) changes and neurodevelopment in preterm infants. STUDY DESIGN: This retrospective cohort study of Canadian Neonatal Network and Canadian Neonatal Follow-Up Network sites included preterm infants born 2010-2018. Logistic regression and model diagnostics evaluated relationships between changes in z score and velocity of weight and HC from birth to discharge from a tertiary neonatal intensive care unit, discharge to 18-24 months corrected age (CA), and birth to 18-24 months CA and significant cognitive/motor impairment at 18-24 months CA classified using a Bayley Scales of Infant and Toddler Development-Third Edition cognitive or motor composite score <70. RESULTS: In total, 4530 infants (53.0% male) with a mean (SD) gestational age of 26.3 (1.4) weeks and birth weight of 920 (227) g were included. Weight and HC changes were associated with lower odds of significant cognitive/motor impairment including an OR of 0.87 (95% CI: 0.83, 0.91; P < .001) for a 1-g/d increase in weight from discharge to 18-24 months CA and 0.81 (95% CI: 0.75, 0.88; P < .001) for a 1-unit increase in HC z score from birth to 18-24 months CA. Associations were not statistically significant in morbidity-free neonates. Weight and HC gains poorly discriminated between infants with and without significant cognitive/motor impairment (areas under the receiver operating characteristic curve of <0.64). No growth measure had a clinically useful balance of sensitivity and specificity. CONCLUSIONS: Weight and HC changes were associated with significant cognitive/motor impairment but had poor discriminatory capability. Neonatal morbidities may make a larger contribution than postnatal growth to neurodevelopment.

International Variation in the Management of Patent Ductus Arteriosus and Its Association with Infant Outcomes: A Survey and Linked Cohort Study.

OBJECTIVE: To assess whether treating patients with a presymptomatic patent ductus arteriosus (PDA), based on early routine echocardiography, performed regardless of clinical signs, improved outcomes. STUDY DESIGN: This multicenter, survey-linked retrospective cohort study used an institutional-level questionnaire and individual patient-level data and included infants of <29 weeks of gestation born in 2014-2016 and admitted to tertiary neonatal intensive care units (NICUs) of 9 population-based national or regional neonatal networks. Infants in NICUs receiving treatment of presymptomatic PDA identified by routine echocardiography and those not were compared for the primary composite outcome (early death [≤7 days after birth] or severe intraventricular hemorrhage) and secondary outcomes (any in-hospital mortality and major morbidities). RESULTS: The unit survey (response rates of 86%) revealed a wide variation among networks in the treatment of presymptomatic PDA (7%-86%). Among 246 NICUs with 17 936 infants (mean gestational age of 26 weeks), 126 NICUs (51%) with 7785 infants treated presymptomatic PDA. The primary outcome of early death or severe intraventricular hemorrhage was not significantly different between the NICUs treating presymptomatic PDA and those who did not (17% vs 21%; aOR 1.00, 95% CI 0.85-1.18). The NICUs treating presymptomatic PDA had greater odds of retinopathy of prematurity treatment (13% vs 7%; aOR 1.47, 95% CI 1.01-2.12); however, it was not significant in a sensitivity analysis excluding Japanese data. CONCLUSIONS: Treating presymptomatic PDA detected by routine echocardiography was commonplace but associated with no significant benefits. Well-designed trials are needed to assess the efficacy and safety of early targeted PDA treatment.

Impact of Deferred Cord Clamping on Mortality and Severe Neurologic Injury in Twins Born at <30 Weeks of Gestation.

OBJECTIVE: To determine whether deferred cord clamping (DCC) compared with early cord clamping (ECC) was associated with reduction in death and/or severe neurologic injury among twins born at <30 weeks of gestation. STUDY DESIGN: We performed a retrospective cohort study including all liveborn twins of <30 weeks admitted to a tertiary-level neonatal intensive care unit (NICU) in Canada between 2015 and 2018 using the Canadian Neonatal/Preterm Birth Network database. We compared DCC ≥30 seconds vs ECC <30 seconds. Our primary outcome was a composite of death and/or severe neurologic injury (severe intraventricular hemorrhage grade III/IV and/or periventricular leukomalacia). Secondary outcomes included neonatal morbidity and health care utilization outcomes. We calculated aORs and ß coefficients for categorical and continuous variables, along with 95% CI. Models were fitted with generalized estimated equations accounting for twin correlation. RESULTS: We included 1597 twins (DCC, 624 [39.1%]; ECC, 973 [60.9%]). Death/severe neurologic injury occurred in 17.8% (n = 111) of twins who received DCC and in 21.7% (n = 211) of those who received ECC. The rate of death/severe neurologic injury did not differ significantly between the DCC and ECC groups (aOR 1.07; 95% CI, 0.78-1.47). DCC was associated with reduced blood transfusions (adjusted ß coefficient, -0.49; 95% CI, -0.86 to -0.12) and NICU length of stay (adjusted ß coefficient, -4.17; 95% CI, -8.15 to -0.19). CONCLUSIONS: The primary composite outcome of death and/or severe neurologic injury did not differ between twins born at <30 weeks of gestation who received DCC and those who received ECC, but DCC was associated with some benefits.

Variations in Neonatal Length of Stay of Babies Born Extremely Preterm: An International Comparison Between iNeo Networks.

OBJECTIVE: To compare length of stay (LOS) in neonatal care for babies born extremely preterm admitted to networks participating in the International Network for Evaluating Outcomes of Neonates (iNeo). STUDY DESIGN: Data were extracted for babies admitted from 2014 to 2016 and born at 24 to 28 weeks of gestational age (n = 28 204). Median LOS was calculated for each network for babies who survived and those who died while in neonatal care. A linear regression model was used to investigate differences in LOS between networks after adjusting for gestational age, birth weight z score, sex, and multiplicity. A sensitivity analysis was conducted for babies who were discharged home directly. RESULTS: Observed median LOS for babies who survived was longest in Japan (107 days); this result persisted after adjustment (20.7 days more than reference, 95% CI 19.3-22.1). Finland had the shortest adjusted LOS (-4.8 days less than reference, 95% CI -7.3 to -2.3). For each week's increase in gestational age at birth, LOS decreased by 12.1 days (95% CI -12.3 to -11.9). Multiplicity and male sex predicted mean increases in LOS of 2.6 (95% CI 2.0-3.2) and 2.1 (95% CI 1.6-2.6) days, respectively. CONCLUSIONS: We identified between-network differences in LOS of up to 3 weeks for babies born extremely preterm. Some of these may be partly explained by differences in mortality, but unexplained variations also may be related to differences in clinical care practices and healthcare systems between countries.

Neonatal Intensive Care Unit-Level Patent Ductus Arteriosus Treatment Rates and Outcomes in Infants Born Extremely Preterm.

OBJECTIVES: To assess associations between neonatal intensive care unit (NICU)-level patent ductus arteriosus (PDA) treatment rates (pharmacologic or surgical) and neonatal outcomes. STUDY DESIGN: This cohort study included infants born at 24-28 weeks of gestation and birth weight <1500 g in 2007-2015 in NICUs caring for ≥100 eligible infants in 6 countries. The ratio of observed/expected (O/E) PDA treatment rates was derived for each NICU by estimating the expected rate using a logistic regression model adjusted for potential confounders and network. The primary composite outcome was death or severe neurologic injury (grades III-IV intraventricular hemorrhage or periventricular leukomalacia). The associations between the NICU-level O/E PDA treatment ratio and neonatal outcomes were assessed using linear regression analyses including a quadratic effect (a square term) of the O/E PDA treatment ratio. RESULTS: From 139 NICUs, 39 096 infants were included. The overall PDA treatment rate was 45% in the cohort (13%-77% by NICU) and the O/E PDA treatment ratio ranged from 0.30 to 2.14. The relationship between the O/E PDA treatment ratio and primary composite outcome was U-shaped, with the nadir at a ratio of 1.13 and a significant quadratic effect (P<.001). U-shaped relationships were also identified with death, severe neurologic injury, and necrotizing enterocolitis. CONCLUSIONS: Both low and high PDA treatment rates were associated with death or severe neurologic injury, whereas a moderate approach was associated with optimal outcomes.

Trends in Outcomes for Neonates Born Very Preterm and Very Low Birth Weight in 11 High-Income Countries.

OBJECTIVE: To evaluate outcome trends of neonates born very preterm in 11 high-income countries participating in the International Network for Evaluating Outcomes of neonates. STUDY DESIGN: In a retrospective cohort study, we included 154 233 neonates admitted to 529 neonatal units between January 1, 2007, and December 31, 2015, at 240/7 to 316/7 weeks of gestational age and birth weight <1500 g. Composite outcomes were in-hospital mortality or any of severe neurologic injury, treated retinopathy of prematurity, and bronchopulmonary dysplasia (BPD); and same composite outcome excluding BPD. Secondary outcomes were mortality and individual morbidities. For each country, annual outcome trends and adjusted relative risks comparing epoch 2 (2012-2015) to epoch 1 (2007-2011) were analyzed. RESULTS: For composite outcome including BPD, the trend decreased in Canada and Israel but increased in Australia and New Zealand, Japan, Spain, Sweden, and the United Kingdom. For composite outcome excluding BPD, the trend decreased in all countries except Spain, Sweden, Tuscany, and the United Kingdom. The risk of composite outcome was lower in epoch 2 than epoch 1 in Canada (adjusted relative risks 0.78; 95% CI 0.74-0.82) only. The risk of composite outcome excluding BPD was significantly lower in epoch 2 compared with epoch 1 in Australia and New Zealand, Canada, Finland, Japan, and Switzerland. Mortality rates reduced in most countries in epoch 2. BPD rates increased significantly in all countries except Canada, Israel, Finland, and Tuscany. CONCLUSIONS: In most countries, mortality decreased whereas BPD increased for neonates born very preterm.

Severe Neurodevelopmental Impairment in Neonates Born Preterm: Impact of Varying Definitions in a Canadian Cohort.

OBJECTIVE: To assess the impact of variations in the definition of severe neurodevelopmental impairment (NDI) on the incidence of severe NDI and the association with risk factors using the Canadian Neonatal Follow-Up Network cohort. STUDY DESIGN: Literature review of severe NDI definitions and application of these definitions were performed in this database cohort study. Infants born at 23-28 completed weeks of gestation between 2009 and 2011 (n = 2187) admitted to a Canadian Neonatal Network neonatal intensive care unit and assessed at 21 months' corrected age were included. The incidence of severe NDI, aORs, and 95% CIs were calculated to express the relationship between risk factors and severe NDI using the definitions with the highest and the lowest incidence rates of severe NDI. RESULTS: The incidence of severe NDI ranged from 3.5% to 14.9% (highest vs lowest rate ratio 4.29; 95% CI 3.37-5.47). The associations between risk factors and severe NDI varied depending on the definition used. Maternal ethnicity, employment status, antenatal corticosteroid treatment, and gestational age were not associated consistently with severe NDI. Although maternal substance use, sex, score of neonatal acute physiology >20, late-onset sepsis, bronchopulmonary dysplasia, and brain injury were consistently associated with severe NDI irrespective of definition, the strength of the associations varied. CONCLUSIONS: The definition of severe NDI significantly influences the incidence and the associations between risk factors and severe NDI. A standardized definition would facilitate site comparisons and scientific communication.

Neonatal Outcomes of Very Low Birth Weight and Very Preterm Neonates: An International Comparison.

OBJECTIVE: To compare rates of a composite outcome of mortality or major morbidity in very-preterm/very low birth weight infants between 8 members of the International Network for Evaluating Outcomes. STUDY DESIGN: We included 58 004 infants born weighing <1500 g at 24(0)-31(6) weeks' gestation from databases in Australia/New Zealand, Canada, Israel, Japan, Spain, Sweden, Switzerland, and the United Kingdom. We compared a composite outcome (mortality or any of grade ≥3 peri-intraventricular hemorrhage, periventricular echodensity/echolucency, bronchopulmonary dysplasia, or treated retinopathy of prematurity) between each country and all others by using standardized ratios and pairwise using logistic regression analyses. RESULTS: Despite differences in population coverage, included neonates were similar at baseline. Composite outcome rates varied from 26% to 42%. The overall mortality rate before discharge was 10% (range: 5% [Japan]-17% [Spain]). The standardized ratio (99% CIs) estimates for the composite outcome were significantly greater for Spain 1.09 (1.04-1.14) and the United Kingdom 1.16 (1.11-1.21), lower for Australia/New Zealand 0.93 (0.89-0.97), Japan 0.89 (0.86-0.93), Sweden 0.81 (0.73-0.90), and Switzerland 0.77 (0.69-0.87), and nonsignificant for Canada 1.04 (0.99-1.09) and Israel 1.00 (0.93-1.07). The adjusted odds of the composite outcome varied significantly in pairwise comparisons. CONCLUSIONS: We identified marked variations in neonatal outcomes between countries. Further collaboration and exploration is needed to reduce variations in population coverage, data collection, and case definitions. The goal would be to identify care practices and health care organizational factors, which has the potential to improve neonatal outcomes.