Supplemental Iodide for Preterm Infants and Developmental Outcomes at 2 Years: An RCT

Select micronutrients for the preterm neonate

If premature neonates are not provided with adequate nutrition, they will quickly become deficient because of increased requirements and a lack of nutrient stores to achieve adequate growth. The provision of many of the recommended micronutrients for pediatric and adult patients is challenging in premature neonates because of the limited data surrounding the true needs of premature neonates and the difficulty in assessing adequate serum levels of these nutrients in this patient population. Parenteral and enteral nutrition shortages further complicate providing adequate micronutrients to premature neonates. This review will discuss select micronutrients and their importance to the preterm neonate, with special emphasis on micronutrients with limited evidence and more challenging supplementation and repletion strategies.

Strengthening Reporting of Neonatal Trials

BACKGROUND AND OBJECTIVES

There is variability in the selection and reporting of outcomes in neonatal trials with key information frequently omitted. This can impact applicability of trial findings to clinicians, families, and caregivers, and impair evidence synthesis. The Neonatal Core Outcomes Set describes outcomes agreed as clinically important that should be assessed in all neonatal trials, and Consolidated Standards of Reporting Trials (CONSORT)-Outcomes 2022 is a new, harmonized, evidence-based reporting guideline for trial outcomes. We reviewed published trials using CONSORT-Outcomes 2022 guidance to identify exemplars of neonatal core outcome reporting to strengthen description of outcomes in future trial publications.

METHODS

Neonatal trials including >100 participants per arm published between 2015 to 2020 with a primary outcome included in the Neonatal Core Outcome Set were identified. Primary outcome reporting was reviewed using CONSORT 2010 and CONSORT-Outcomes 2022 guidelines by assessors recruited from Cochrane Neonatal. Examples of clear and complete outcome reporting were identified with verbatim text extracted from trial reports.

RESULTS

Thirty-six trials were reviewed by 39 assessors. Examples of good reporting for CONSORT 2010 and CONSORT-Outcomes 2022 criteria were identified and subdivided into 3 outcome categories: "survival," "short-term neonatal complications," and "long-term developmental outcomes" depending on the core outcomes to which they relate. These examples are presented to strengthen future research reporting.

CONCLUSIONS

We have identified examples of good trial outcome reporting. These illustrate how important neonatal outcomes should be reported to meet the CONSORT 2010 and CONSORT-Outcomes 2022 guidelines. Emulating these examples will improve the transmission of information relating to outcomes and reduce associated research waste.

Proportion of Infant Neurodevelopment Trials Reporting a Null Finding: A Systematic Review

CONTEXT

Discovering new interventions to improve neurodevelopmental outcomes is a priority; however, clinical trials are challenging and methodological issues may impact the interpretation of intervention efficacy.

OBJECTIVES

Characterize the proportion of infant neurodevelopment trials reporting a null finding and identify features that may contribute to a null result.

DATA SOURCES

The Cochrane library, Medline, Embase, and CINAHL databases.

STUDY SELECTION

Randomized controlled trials recruiting infants aged <6 months comparing any "infant-directed" intervention against standard care, placebo, or another intervention. Neurodevelopment assessed as the primary outcome between 12 months and 10 years of age using a defined list of tools.

DATA EXTRACTION

Two reviewers independently extracted data and assessed quality of included studies.

RESULTS

Of n = 1283 records screened, 21 studies (from 20 reports) were included. Of 18 superiority studies, >70% reported a null finding. Features were identified that may have contributed to the high proportion of null findings, including selection and timing of the primary outcome measure, anticipated effect size, sample size and power, and statistical analysis methodology and rigor.

LIMITATIONS

Publication bias against null studies means the proportion of null findings is likely underestimated. Studies assessing neurodevelopment as a secondary or within a composite outcome were excluded.

CONCLUSIONS

This review identified a high proportion of infant neurodevelopmental trials that produced a null finding and detected several methodological and design considerations which may have contributed. We make several recommendations for future trials, including more sophisticated approaches to trial design, outcome assessment, and analysis.

Fifteen-minute consultation: ABCDE approach to nutritional assessment in preterm infants

The last 20 years has seen dramatic improvements in the survival of preterm infants due to improved antenatal and neonatal care. Closer attention to nutrition means early parenteral nutrition and mother's own milk are considered as standard of care. Many uncertainties remain however, such as optimal macronutrient intakes for longer term cognitive and metabolic outcomes, and the optimal probiotic regime to reduce the risk of necrotising enterocolitis. Nutrition involves macronutrients and micronutrients, immunonutrients, microbiomic aspects and nutrient delivery. It is also clear that there are behavioural and psychological aspects, and strongly held beliefs for parents and professionals that affect practice. While many healthcare professionals (HCPs) are aware of several key nutritional concepts on the neonatal intensive care unit (NICU), many HCPs lack a concise, systematic approach. This article provides a brief approach to nutritional assessment for use on the NICU summarised as ABCDE: A-anthropometry, B-biochemistry, C-clinical, D-dietary intakes, E-environment and evaluation.

Necrotising enterocolitis, late-onset sepsis and mortality after routine probiotic introduction in the UK

OBJECTIVE

To compare necrotising enterocolitis (NEC), late-onset sepsis (LOS), focal intestinal perforation (FIP) and mortality in infants from a single neonatal unit before and after probiotic introduction.

DESIGN

Retrospective review of infants <32 weeks admitted January 2009-December 2012 (no probiotic) and January 2013-December 2017 (routine probiotics). Infants included were admitted before day 3, and not transferred out before day 3. NEC, LOS and FIP were defined with standard definitions.

PATIENTS

1061 infants were included, 509 preprobiotic and 552 postprobiotic. Median gestation, birth weight and antenatal steroid use did not differ, and proportions of extremely low birthweight infants were similar (37% and 41%).

RESULTS

Overall unadjusted risk of NEC (9.2% (95% CI 7.1 to 12.1) vs 10.6% (95% CI 8.2 to 13.4), p=0.48), LOS (16.3% (95% CI 13.2 to 19.6) vs 14.1% (95% CI 11.5 to 17.4), p=0.37) and mortality (9.2% (95% CI 7.1 to 12.1) vs 9.7% (95% CI 7.6 to 12.6), p=0.76) did not differ, nor proportion of surgical NEC. In multiple logistic regression, accounting for gestation, birth weight, antenatal steroid, maternal milk, chorioamnionitis and sex, probiotic receipt was not significantly associated with NEC (adjusted OR (aOR) 1.08 (95% CI 0.71 to 1.68), p=0.73), LOS or mortality. In subgroup (645 infants) >28 weeks, aOR for NEC in the probiotic cohort was 0.42 (95% CI 0.2 to 0.99, p=0.047). FIP was more common in the probiotic cohort (OR 2.3 (95% CI 1.0 to 5.4), p=0.04), not significant in regression analysis (2.11 (95% CI 0.97 to 4.95), p=0.05).

CONCLUSIONS

Probiotic use in this centre did not reduce overall mortality or rates of NEC, LOS or FIP but subgroup analysis identified NEC risk reduction in infants >28 weeks, and LOS reduction <28 weeks.

Postnatal Serum Total Thyroxine Level Associated with Short- and Long-Term Anthropometric Outcomes in Very Preterm Infants

Thyroxine (T4) importantly regulates the growth of newborns. Compared to fetuses with equivalent gestational ages, very preterm infants (VPIs) often experience relatively low thyroxinemia, with a normal thyroid-stimulating hormone (TSH) concentration < 10 μIU/mL. However, there is continued debate regarding postnatal thyroxine supplementation for VPIs with normal TSH and transitionally low thyroxinemia. Little research has explored the role of the postnatal total T4 (TT4) serum concentration on the growth of VPIs. In this study, we aim to clarify whether the postnatal thyroxine concentration is associated with the short- and long-term growth outcomes of VPIs. A total of 334 surviving VPIs in our previously reported cohort, born in the period August 2007−July 2016, were enrolled. The exposure variable was the postnatal TT4 concentration at 1 month old. The primary outcomes were body weight increments over 28 days after the screening and anthropometric outcomes at the corrected age of 24 months old. Infants with any hormonal replacement, severe brain injury, congenital anomaly, or cerebral palsy were excluded. In total, 290 (86.8%) VPIs were included for analysis. In the 28 days after thyroid function screening, the TT4 concentration was found to have a significant association with positive increments in body weight (mean increment: 25.7 g per 1 μg/dL; p < 0.001) and a positive body weight z-score (mean increment: 0.039 per 1 μg/dL; p = 0.037), determined by generalized estimating equation analysis. At the corrected age of 24 months old, a higher postnatal TT4 concentration was associated with a lower body mass index (mean coefficient: −0.136; 95% CI: −0.231 to −0.041, p = 0.005) and lower body mass index z-score (mean coefficient: −0.097; 95% CI: −0.170 to −0.024, p = 0.009). Infants with a TT4 concentration > 6.4 ug/dL had significantly lower odds of overweight status (odds ratio: 0.365; 95% CI: 0.177 to 0.754, p = 0.006). We conclude that the postnatal TT4 concentration is associated with a positive increment in body weight in the short term. At the same time, the postnatal TT4 concentration is associated with lower odds of overweight status after long-term follow-up.

The Role of Iodine for Thyroid Function in Lactating Women and Infants

Iodine is a micronutrient needed for the production of thyroid hormones, which regulate metabolism, growth, and development. Iodine deficiency or excess may alter the thyroid hormone synthesis. The potential effects on infant development depend on the degree, timing, and duration of exposure. The iodine requirement is particularly high during infancy because of elevated thyroid hormone turnover. Breastfed infants rely on iodine provided by human milk, but the iodine concentration in breast milk is determined by the maternal iodine intake. Diets in many countries cannot provide sufficient iodine, and deficiency is prevented by iodine fortification of salt. However, the coverage of iodized salt varies between countries. Epidemiological data suggest large differences in the iodine intake in lactating women, infants, and toddlers worldwide, ranging from deficient to excessive intake. In this review, we provide an overview of the current knowledge and recent advances in the understanding of iodine nutrition and its association with thyroid function in lactating women, infants, and toddlers. We discuss risk factors for iodine malnutrition and the impact of targeted intervention strategies on these vulnerable population groups. We highlight the importance of appropriate definitions of optimal iodine nutrition and the need for more data assessing the risk of mild iodine deficiency for thyroid disorders during the first 2 years in life.

Multi-level hypothalamic neuromodulation of self-regulation and cognition in preterm infants: Towards a control systems model

Preterm infants, age-corrected for prematurity, score on average, 10 points lower on IQ tests than full-term infants tested at comparable ages. This review focuses on the potential contribution of the hypothalamus to cognitive neuro-regulatory development in preterm infants through its bidirectional neural connections with the prefrontal cortex and its neuroendocrine activity. It aims to clarify the central role of the hypothalamus in preterm high stress situations and in influencing cognitive development via its connectivity to the cerebral cortex. The review further evaluates epigenomic sensitivity to environmental inputs. Recent results suggest that an optimal range of DNA methylations (via a continuous process of decreasing levels of receptor methylations that are too high, and increasing levels that are too low) appears necessary in order to reach an adaptive level of receptor availability. Several studies have demonstrated amelioration of preterm infants' stress while in the Newborn Intensive Care Unit (NICUs) and following discharge. The authors postulate that feedback mechanisms and correction signals are the basis for a hypothalamic homeostatic modulating function, a "hypothalamic resistance response", which may account for the stress reduction brought about by in- and post-NICU early interventions and their results of promoting self-regulation and cognition.

Thyroid function and dysfunction in preterm infants-Challenges in evaluation, diagnosis and therapy

Thyroid hormone levels have a crucial role for optimal brain development from gestation through the first 2 postnatal years. However, thyroid hormones vary with gestational age, and their levels vary between term and preterm infants. Preterm newborns are prone to thyroid dysfunction which is now more frequently observed with the advances of neonatal care and improved survival of extremely premature infants. Thus, hypothyroxinaemia of prematurity associated with delayed TSH elevation is very common in low birth weight premature infants most likely due to the immaturity of the hypothalamic-pituitary thyroid axis. Furthermore, postnatal illness, medications and iodine status may contribute to the thyroid dysfunction or affect the interpretation of the thyroid function tests. Despite available guidelines, timing of screening and optimal treatment of thyroid dysfunction in premature infants remains controversial. Furthermore, it is unknown whether untreated thyroid dysfunction in premature babies affects neurodevelopmental outcome. In the vast majority of preterm infants, hypothyroxinaemia is transient; however, permanent hypothyroidism due to thyroid dysgenesis or enzyme defects might also occur. Therefore, careful monitoring of thyroid function and long-term follow-up is needed to assess an appropriate therapeutic approach. This article reviews thyroid physiology in preterm infants, the influences of gestation and other neonatal conditions on thyroid function tests, optimal timing of screening and possible predictors to differentiate transient hypothyroxinaemia from permanent hypothyroidism.

Eligibility Criteria and Representativeness of Randomized Clinical Trials That Include Infants Born Extremely Premature: A Systematic Review

OBJECTIVE

To assess the eligibility criteria and trial characteristics among contemporary (2010-2019) randomized clinical trials (RCTs) that included infants born extremely preterm (<28 weeks of gestation) and to evaluate whether eligibility criteria result in underrepresentation of high-risk subgroups (eg, infants born at <24 weeks of gestation).

STUDY DESIGN

PubMed and Scopus were searched January 1, 2010, to December 31, 2019, with no language restrictions. RCTs with mean or median gestational ages at birth of <28 weeks of gestation were included. The study followed the PRISMA guidelines; outcomes were registered prospectively. Data extraction was performed independently by multiple observers. Study quality was evaluated using a modified Jadad scale.

RESULTS

Among RCTs (n = 201), 32 552 infants were included. Study participant characteristics, interventions, and outcomes were highly variable. A total of 1603 eligibility criteria were identified; rationales were provided for 18.8% (n = 301) of criteria. Fifty-five RCTs (27.4%) included infants <24 weeks of gestation; 454 (1.4%) infants were identified as <24 weeks of gestation.

CONCLUSIONS

The present study identifies sources of variability across RCTs that included infants born extremely preterm and reinforces the critical need for consistent and transparent policies governing eligibility criteria.

Iodine supplementation: is there a need?

PURPOSE OF REVIEW

To review the recent data on iodine deficiency, the impact of iodine deficiency on health outcomes and the need for iodine supplementation in at-risk populations, that is, pregnant and lactating women, infants and young children.

RECENT FINDINGS

The 2019 Iodine Global Network Annual Report highlighted that only 23 countries worldwide (including Finland, Germany, and Norway in Europe) were classified as having insufficient iodine intake in 2019, down from 54 in 2003 and 113 in 1993. Even if severe iodine deficiency during pregnancy has a negative impact on cognitive outcomes later in life, the consequences of mild-to-moderate iodine deficiency on child neurodevelopment are controversial. Two 2017 and 2019 Cochrane Systematic Reviews found no evidence that iodine supplementation in women before, during or after pregnancy improved infant and child cognitive development in areas with mild-to-moderate iodine deficiency. Likewise, a 2019 Cochrane systematic review concluded that there was no evidence of a positive impact of iodine supplementation on morbidity, including cognitive impairment, and mortality in preterm infants.

SUMMARY

There is no scientific evidence to support generalized iodine supplementation in mildly to moderately deficient settings not only in pregnant and lactating women but also in infants, either preterm or term, and in young children.

Postnatal Serum Total Thyroxine of Very Preterm Infants and Long-Term Neurodevelopmental Outcome

Primary congenital hypothyroidism is a disease associated with low serum thyroxine and elevated thyroid-stimulating hormone (TSH) levels. The processes of screening and treating congenital hypothyroidism, in order to prevent neurodevelopmental impairment (NDI) in newborns, have been well investigated. Unlike term infants, very preterm infants (VPIs) may experience low thyroxine with normal TSH levels (<10.0 μIU/mL) during long-stay hospitalization. In the current literature, thyroxine treatment has been evaluated only for TSH-elevated VPIs. However, the long-term impact of low thyroxine levels in certain VPIs with normal TSH levels deserves more research. Since July 2007, VPIs of this study unit received screenings at 1 month postnatal age (PNA) for serum TSH levels and total thyroxine (TT4), in addition to two national TSH screenings scheduled at 3–5 days PNA and at term equivalent age. This study aimed to establish the correlation between postnatal 1-month-old TT4 concentration and long-term NDI at 24 months corrected age among VPIs with serial normal TSH levels. VPIs born in August 2007–July 2016 were enrolled. Perinatal demography, hospitalization morbidities, and thyroid function profiles were analyzed, and we excluded those with congenital anomalies, brain injuries, elevated TSH levels, or a history of thyroxine treatments. In total, 334 VPIs were analyzed and 302 (90.4%) VPIs were followed-up. The postnatal TT4 concentration was not associated with NDI after multivariate adjustment (odd ratios 1.131, 95% confidence interval 0.969–1.32). To attribute the NDI of TSH-normal VPIs to a single postnatal TT4 concentration measurement may require more research.

Thyroid function in preterm infants and neurodevelopment at 2 years

OBJECTIVES

Postnatal thyroid dysfunction is common in preterm infants but the relationship between mild dysfunction and neurodevelopment is unclear. Our aim is to describe the relationship between thyroid function and neurodevelopment.

DESIGN

Cohort analysis.

PATIENTS

1275 infants born under 31 weeks' gestation; there were no exclusion criteria.

SETTING

The infants were part of a UK daily iodine supplementation trial.

MAIN OUTCOMES

Thyroid-stimulating hormone, thyroid-binding globulin and total thyroxine levels were measured in dried blood spots on postnatal days 7, 14, 28 and the equivalent of 34 weeks' gestation. Neurodevelopment was measured using the Bayley-III Scales of infant development at 2 years of age.

RESULTS

No infant was identified as hypothyroid through routine screening. The 3% of infants consistently in the top decile of gestationally age-adjusted thyroid-stimulating hormone levels had a reduction in cognitive score of 7 Bayley units when compared with those not in the top decile (95% CI -13 to -1). A reduction in motor composite score of 6 units (95% CI -12 to <-0.1) and fine motor score of 1 unit (95% CI -2 to -0.1) was also identified. The 0.7% of infants consistently in the bottom decile of age-adjusted thyroxine levels had a reduction in motor composite score of 14 units (95% CI -25 to -2) and its two subset scores, fine and gross motor, of 2 units (95% CI respectively -4.5 to <-0.1 and -4.3 to -0.3).

CONCLUSIONS

Preterm infants with consistent 'mild' thyroid dysfunction score less on neurodevelopmental tests at 2 years of age. Many of these infants will not be detected by current clinical protocols or screening programmes.

Neonatal Thyroid Function and Disorders

Thyroid hormone is essential for normal fetal brain development in utero and for the first 2 years of life. The developing fetus is initially reliant upon maternal thyroid hormones that cross the placenta, until the fetal thyroid begins to supply thyroid hormone for the fetus. Maternal thyroid status affects fetal thyroid function and maternal thyroid dysfunction can have a significant impact on the fetus and neonate. There are also several neonatal factors that can influence thyroid function. Here, we describe thyroid function in the fetus and neonate and discuss the most common thyroid disorders seen in neonates.

Postnatal Nutrition to Improve Brain Development in the Preterm Infant: A Systematic Review From Bench to Bedside

Background: Preterm infants are at high risk for Encephalopathy of Prematurity and successive adverse neurodevelopmental outcome. Adequate nutrition is crucial for healthy brain development. Maternal breast milk is first choice of post-natal enteral nutrition for preterm infants. However, breast milk contains insufficient nutrient quantities to meet the greater nutritional needs of preterm infants, meaning that supplementation is recommended. Aim: To provide an overview of current literature on potential nutritional interventions for improvement of neurodevelopmental outcome in preterm infants, by taking a bench to bedside approach from pre-clinical models of neonatal brain injury to randomized controlled clinical trials (RCTs) in preterm infants. Methods: Separate clinical and pre-clinical searches were performed in Medline and Embase for English written papers published between 08/2008 and 08/2018 that studied a single nutritional component. Papers were included if one of the following components was studied: lipids, carbohydrates, proteins, vitamins, minerals, probiotics, prebiotics, oligosaccharides, fatty acids, or amino acids, with brain injury, brain development or neurodevelopmental outcome as outcome measure in preterm infants (gestational age <32 weeks and/or birth weight <1,500 g) or in animal models of neonatal brain injury. Results: In total, 2,671 pre-clinical studies and 852 RCTs were screened, of which 24 pre-clinical and 22 RCTs were included in this review. In these trials supplementation with amino acids and protein, lipids, probiotics (only clinical), prebiotics (only clinical), vitamins, and minerals was studied. All included pre-clinical studies show positive effect of supplementation on brain injury and/or neurodevelopment. Although some nutrients, such as glutamine, show promising short term outcome in clinical studies, no evident long term effect of any supplemented nutrient was found. Main limitations were inclusion of studies no older than 10 years at time of search and studies that focused on single nutritional components only. Conclusion: Even though many pre-clinical trials demonstrate promising effects of different nutritional interventions on reducing brain injury and/or improving neurodevelopmental outcome, these positive effects have so far not evidently been demonstrated in RCTs. More clinically relevant animal models and long term follow up after clinical trials are needed to move novel nutritional therapies from bench to bedside of preterm infants.

Iodine supplementation for the prevention of mortality and adverse neurodevelopmental outcomes in preterm infants

BACKGROUND

Parenteral nutrition solutions, artificial formulas, and human breast milk contain insufficient iodine to meet recommended intakes for preterm infants. Iodine deficiency may exacerbate transient hypothyroxinaemia in preterm infants and this may be associated with adverse neonatal and longer-term outcomes.

OBJECTIVES

To assess the evidence from randomised controlled trials that dietary supplementation with iodine reduces mortality and morbidity in preterm infants.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL 2018, Issue 1), Ovid MEDLINE, Ovid Embase, Ovid Maternity & Infant Care Database, and CINAHL to February 2018. We searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that compared supplementing enteral or parenteral feeds with iodine (as iodide salt) versus placebo or no supplementation in preterm infants.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility and risk of bias, and extracted data. We analysed treatment effects as described in the individual trials and reported risk ratios (RR) and risk differences for dichotomous data, and mean differences (MD) for continuous data, with 95% confidence intervals (CI). We used a fixed-effect model in meta-analyses and planned to explore potential causes of heterogeneity in sensitivity analyses. We used the GRADE approach to assess the quality of evidence.

MAIN RESULTS

Two randomised controlled trials fulfilled the eligibility criteria. Both trials used methods to limit bias including allocation concealment and blinding of clinicians and investigators to the allocated intervention. The trials enrolled 1394 infants. One trial recruited 1273 participants. Most participants were born very preterm (less than 32 weeks' gestation) and about one-third were extremely preterm (less than 28 weeks' gestation). Analyses found no effect of iodine supplementation on mortality before hospital discharge (typical RR 1.01, 95% CI 0.72 to 1.42; 2 studies, 1380 infants) or on neurodevelopmental assessments at two years post-term (Bayley Scales of Infant and Toddler Development, Third Edition main domain composite scores: cognitive: MD -0.30, 95% CI -2.44 to 1.84; motor: MD 0.20, 95% CI -2.15 to 2.55; language: MD -0.10, 95% CI -2.50 to 2.30; 1 study, 1259 infants). There were no differences in the proportion of infants who died or had a composite score less than 85 in any main Bayley domain (RR 1.05, 95% CI 0.94 to 1.17; 1 study, 1259 infants), or had visual impairment (RR 0.63, 95% CI 0.28 to 1.45; 1 study, 1092 infants) or auditory impairment (RR 1.05, 95% CI 0.51 to 2.16; 1 study, 1093 infants). Using GRADE methods, we assessed the evidence for the effects on mortality and neurodevelopment outcomes as high-certainty.

AUTHORS' CONCLUSIONS

The available trial data, predominantly from one large, high-quality multicentre study published in 2017, do not show any evidence of beneficial effects of iodine supplementation for preterm infants. Given the high certainty of these estimates of effect, further trials of this intervention in this population are unlikely to be considered research priorities.