Postnatal maximal weight loss, fluid administration, and outcomes in extremely preterm newborns

Expected and Desirable Preterm and Small Infant Growth Patterns

Adequate nutrition is necessary for achieving optimal growth and neurodevelopment. Growth is a natural and expected process that happens concomitantly with rapid advancements in neurodevelopment. Serial weight, length, and head circumference growth measures are essential for monitoring development, although identifying pathological deviations from normal growth can pose challenges. Appropriate growth assessments require considerations that a range of sizes for length, head circumference, and weight are expected and appropriate. Because of genetic differences and morbidities, there is a considerable overlap between the growth of healthy infants and those with growth alterations. Parents tend to be over-concerned about children who plot low on growth charts and often need reassurance. Thus, the use of terms such as "poor" growth or growth "failure" are discouraged when growth is approximately parallel to growth chart curves even if their size is smaller than specific percentiles. No specific percentile should be set as a growth goal; individual variability should be expected. An infant's size at birth is important information that goes beyond the common use of prognostic predictions of appropriate compared with small or large for gestational age. The lower the birthweight, the lower the nutrient stores and the more important the need for nutrition support. Compared to term infants, preterm infants at term-equivalent age have a higher percentage of body fat, but this diminishes over the next months. Current research findings support expert recommendations that preterm infants should grow, after early postnatal weight loss, similar to the fetus and then term-born infants, which translates to growth approximately parallel to growth chart curves. There is no need for a trade-off between optimum cognition and optimum future health. Each high-risk infant needs individualized nutrition and growth assessments. This review aims to examine infant growth expectations and messaging for parents of preterm and term-born infants within the broader causal framework.

Time to regain birthweight and association with neurodevelopmental outcomes among extremely preterm newborns

OBJECTIVE

Determine association between time to regain birthweight and 2-year neurodevelopment among extremely preterm (EP) newborns.

STUDY DESIGN

Secondary analysis of the Preterm Erythropoietin Neuroprotection Trial evaluating time to regain birthweight, time from birth to weight nadir, time from nadir to regain birthweight, and cumulative weight loss with 2-year corrected Bayley Scales of Infant and Toddler Development 3rd edition.

RESULTS

Among n = 654 EP neonates, those with shorter nadir-to-regain had lower cognitive scores (≤1 day versus ≥8 days: -5.0 points, [CI -9.5, -0.6]) and lower motor scores (≤1 day versus ≥8 days: -4.6 points [CI -9.2, -0.03]) in adjusted stepwise forward regression modeling. Increasingly cumulative weight loss was associated with lower cognitive scores (≤-50 percent-days: -5.6, [CI -9.4, -1.8]), motor scores (≤-50 percent-days: -4.2, [CI -8.2, -0.2]); and language scores (≤-50 percent-days: -6.0, [CI -10.1, -1.9]).

CONCLUSION

Faster nadir-to-regain and excessive cumulative weight loss are associated with adverse 2-year neurodevelopmental outcomes.

TRIAL REGISTRATION

PENUT Trial Registration: NCT01378273. https://clinicaltrials.gov/ct2/show/NCT01378273 .

CLINICAL TRIAL REGISTRATION

This study is a post-hoc secondary analysis of pre-existing data from the PENUT Trial (NCT #01378273).

Fluid and electrolyte management in the neonate and what can go wrong

PURPOSE OF REVIEW

This review highlights recent advances in understanding fluid and electrolyte homeostasis during the newborn period, including heightened recognition of fluid overload and acute kidney injury contributing to poor clinical outcomes. Particular attention is given towards the care of extremely preterm infants.

RECENT FINDINGS

Emerging data demonstrate (i) disproportionally large transepidermal water loss in the extremely preterm population, (ii) the relationship between postnatal weight loss (negative fluid balance) and improved outcomes, (iii) the frequency and negative effects of dysnatremias early in life, (iv) the role of sodium homeostasis in optimizing postnatal growth, and (v) the deleterious effects of fluid overload and acute kidney injury.

SUMMARY

As clinicians care for an increasing number of preterm infants, understanding progress in approaches to fluid and electrolyte management and avoidance of fluid overload states will improve the care and outcomes of this vulnerable population. Further translational and clinical studies are needed to address remaining knowledge gaps and improve current approaches to fluid and electrolyte management.

Risk factors and epidemiology of spontaneous intestinal perforation among infants born at 22-24 weeks' gestational age

OBJECTIVE

To describe the epidemiology, risk factors, and timing of spontaneous intestinal perforation (SIP) among infants born at 22-24 weeks' gestational age (GA).

STUDY DESIGN

Observational cohort study among infants born at 22-24 weeks' GA in 446 neonatal intensive care units.

RESULTS

We identified 9712 infants, of whom 379 (3.9%) developed SIP. SIP incidence increased with decreasing GA (P < 0.001). Antenatal magnesium (odds ratio (OR) 1.42; 95% confidence interval (CI), 1.09-1.85), antenatal indomethacin (OR 1.40; 95% CI, 1.06-1.85), postnatal indomethacin (OR 1.61; 95% CI, 1.23-2.11), and postnatal hydrocortisone exposure (OR 2.02; 95% CI 1.50-2.73) were associated with SIP. Infants who lost 15-20% (OR 1.77; 95% CI, 1.28-2.44) or >20% (OR 2.04; 95% CI, 1.46-2.85) of birth weight had higher odds of SIP than infants with weight loss <10%.

CONCLUSIONS

Antenatal magnesium exposure, antenatal indomethacin exposure, postnatal hydrocortisone exposure, postnatal indomethacin exposure, and weight loss ≥15% were associated with SIP.

Time to Regain Birthweight and Association with Neurodevelopmental Outcomes among Extremely Preterm Newborns

Objective

Determine association between time to regain birthweight and 2-year neurodevelopment among extremely preterm (EP) newborns.

Study Design

Secondary analysis of the Preterm Erythropoietin Neuroprotection Trial evaluating time to regain birthweight, time from birth to weight nadir, time from nadir to regain birthweight, and cumulative weight loss with 2-year corrected Bayley Scales of Infant and Toddler Development 3rd edition.

Results

Among n = 654 EP neonates, those with shorter nadir-to-regain had lower cognitive scores (2-4 days versus ≥ 8 days: -3.5, [CI -7.0, 0.0]; ≤1 day versus ≥ 8 days: -5.0, [CI -10.2, 0.0]) in fully adjusted stepwise forward regression modeling. Increasingly cumulative weight loss was associated with lower cognitive scores (-50 to <-23 percent-days: -4.0, [95% CI -7.6, -0.4]) and language scores (≤-50 percent-days: -5.7, [CI -9.8, -1.6]; -50 to <-23 percent-days: -6.1, [CI -10.2, -2.0]).

Conclusion

Faster nadir-to-regain and prolonged, severe weight loss are associated with adverse 2-year neurodevelopmental outcomes.

Trial registration

PENUT Trial Registration: NCT01378273. https://clinicaltrials.gov/ct2/show/NCT01378273.

Early Fluid and Nutritional Management of Extremely Preterm Newborns During the Fetal-To-Neonatal Transition

During the fetal-to-neonatal transitional period, extremely preterm newborns undergo significant intrabody fluid shifts and resulting weight loss due to increased insensible fluid losses due to immature skin, kidneys, among other factors. These ongoing physiologic changes make fluid and nutritional management complex in the neonatal-to-fetal transitional time period for extremely premature newborns. However, limited literature exists to guide optimal practices for providers caring for this population. Here, we review the evidence on optimal fluid and nutritional management during the fetal-to-neonatal transition of extremely preterm newborns.

Increasing Sodium Variability in the First 96 Hours after Birth is Associated with Adverse In-Hospital Outcomes of Preterm Newborns

Background

Neonatal intraventricular hemorrhage prevention bundles for preterm infants commonly defer daily weighing for the first 72 h, with reweighing occurring on day 4. Clinicians rely on maintaining stable sodium values as a proxy of fluid status to inform fluid management decisions over the first 96 h after birth. Yet, there exists a paucity of research evaluating whether serum sodium or osmolality are appropriate proxies for weight loss and whether increasing variability in sodium or osmolality during this early transitional period is associated with adverse in-hospital outcomes.

Objectives

To evaluate whether serum sodium or osmolality change in the first 96 h after birth was associated with percent weight change from birth weight, and to assess potential associations between serum sodium and osmolality variability with in-hospital outcomes.

Methods

This retrospective, cross-sectional study included neonates born at ≤30 gestational weeks or ≤1250 g. We evaluated associations between serum sodium coefficient of variation (CoV), osmolality CoV, and maximal weight loss percentage in the first 96 h after birth with in-hospital neonatal outcomes.

Results

Among 205 infants, serum sodium and osmolality were poorly correlated with percent weight change in individual 24-h increments (R2 = 0.01-0.14). For every 1% increase in sodium CoV, there was an associated 2-fold increased odds of surgical necrotizing enterocolitis and 2-fold increased odds of in-hospital mortality (odds ratio, 2.07; 95% CI: 1.02, 4.54; odds ratio, 1.95; 95% CI: 1.10, 3.64, respectively). Sodium CoV was more strongly associated with outcomes than absolute sodium maximal change.

Conclusions

In the first 96 h, serum sodium and osmolality are poor proxies for assessing percent weight change. Increasing variability of serum sodium is associated with later development of surgical necrotizing enterocolitis and all-cause in-hospital mortality. Prospective research is needed to evaluate whether reducing sodium variability in the first 96 h after birth, as assessed by CoV, improves newborn health outcomes.

Association of Fluid Balance With Short- and Long-term Respiratory Outcomes in Extremely Premature Neonates: A Secondary Analysis of a Randomized Clinical Trial

IMPORTANCE

Extremely low gestational age neonates are at risk of disorders of fluid balance (FB), defined as change in fluid weight over a specific period. Few data exist on the association between FB and respiratory outcomes in this population.

OBJECTIVE

To describe FB patterns and evaluate the association of FB with respiratory outcomes in a cohort of extremely low gestational age neonates.

DESIGN, SETTING, AND PARTICIPANTS

This study is a secondary analysis of the Preterm Erythropoietin Neuroprotection Trial (PENUT), a phase 3 placebo-controlled randomized clinical trial of erythropoietin in extremely premature neonates conducted in 30 neonatal intensive care units in the US from December 1, 2013, to September 31, 2016. This analysis included 874 extremely premature neonates born at 24 to 27 weeks' gestation who were enrolled in the PENUT study. Secondary analysis was performed in November 2021.

EXPOSURES

Primary exposure was peak FB during the first 14 postnatal days. The FB was calculated as percent change in weight from birth weight (BW) as a surrogate for FB.

MAIN OUTCOMES AND MEASURES

The primary outcome was mechanical ventilation on postnatal day 14. The secondary outcome was a composite of severe bronchopulmonary dysplasia (BPD) or death.

RESULTS

A total of 874 neonates (449 [51.4%] male; mean [SD] BW, 801 [188] g; 187 [21.4%] Hispanic, 676 [77.3%] non-Hispanic, and 11 [1.3%] of unknown ethnicity; 226 [25.9%] Black, 569 [65.1%] White, 51 [5.8%] of other race, and 28 [3.2%] of unknown race) were included in this analysis. Of these 874 neonates, 458 (52.4%) received mechanical ventilation on postnatal day 14, and 291 (33.3%) had severe BPD or had died. Median peak positive FB was 11% (IQR, 4%-20%), occurring on postnatal day 13 (IQR, 9-14). A total of 93 (10.6%) never decreased below their BW. Neonates requiring mechanical ventilation at postnatal day 14 had a higher peak FB compared with those who did not require mechanical ventilation (15% above BW vs 8% above BW, P < .001). On postnatal day 3, neonates requiring mechanical ventilation were more likely to have a higher FB (5% below BW vs 8% below BW, P < .001). The median time to return to BW was shorter in neonates who received mechanical ventilation (7 vs 8 days, P < .001) and those with severe BPD (7 vs 8 days, P < .001). After adjusting for confounding variables, for every 10% increase in peak FB during the first 14 postnatal days, there was 103% increased odds of receiving mechanical ventilation at postnatal day 14 (adjusted odds ratio, 2.03; 95% CI, 1.64-2.51).

CONCLUSIONS AND RELEVANCE

In this secondary analysis of a randomized clinical trial, peak FB was associated with mechanical ventilation on postnatal day 14 and severe BPD or death. Fluid balance in the first 3 postnatal days and time to return to BW may be potential targets to help guide management and improve respiratory outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01378273.

Total Fluid Administration and Weight Loss during the First 2 Weeks in Infants Randomized to Early Enteral Feeding after Extremely Preterm Birth

BACKGROUND

Randomized trials have not reported the effects of the early progression of feeding volumes on fluid balance and neurodevelopment among infants born extremely preterm (≤28 weeks).

METHOD

Fluid, electrolyte, and neurodevelopment data of 60 extremely preterm infants randomly assigned to receive either 1 (early feeding group) or 4 days (late feeding group) of trophic feeding volumes at 20-24 mL/kg/day were analyzed.

RESULTS

Infants randomized to the early feeding group received less parenteral fluids, generated lower urine volumes, and had less excessive weight loss during the first 14 days after birth. The 7-point difference in cognitive scores and the 0.5 difference in weight-for-age z-scores favoring the early feeding group did not reach statistical significance.

CONCLUSIONS

In extremely preterm infants, early enteral feeding is associated with less total fluid administration and with less excessive weight loss during the first 2 weeks after birth. These short-term effects could have long-lasting benefits.