Developmental outcome at 12 months corrected age for infants born less than 30 weeks gestation: influence of reduced intrauterine and postnatal growth

Early protein intake predicts functional connectivity and neurocognition in preterm born children

Nutritional intake can promote early neonatal brain development in very preterm born neonates (< 32 weeks’ gestation). In a group of 7-year-old very preterm born children followed since birth, we examined whether early nutrient intake in the first weeks of life would be associated with long-term brain function and neurocognitive skills at school age. Children underwent resting-state functional MRI (fMRI), intelligence testing (Wechsler Intelligence Scale for Children, 5th Ed) and visual-motor processing (Beery-Buktenica, 5th Ed) at 7 years. Relationships were assessed between neonatal macronutrient intakes, functional connectivity strength between thalamic and default mode networks (DMN), and neuro-cognitive function using multivariable regression. Greater functional connectivity strength between thalamic networks and DMN was associated with greater intake of protein in the first week (β = 0.17; 95% CI 0.11, 0.23, p < 0.001) but lower intakes of fat (β = − 0.06; 95% CI − 0.09, − 0.02, p = 0.001) and carbohydrates (β = − 0.03; 95% CI − 0.04, − 0.01, p = 0.003). Connectivity strength was also associated with protein intake during the first month (β = 0.22; 95% CI 0.06, 0.37, p = 0.006). Importantly, greater thalamic-DMN connectivity strength was associated with higher processing speed indices (β = 26.9; 95% CI 4.21, 49.49, p = 0.02) and visual processing scores (β = 9.03; 95% CI 2.27, 15.79, p = 0.009). Optimizing early protein intake may contribute to promoting long-term brain health in preterm-born children.

Preterm infants fed nutrient-enriched formula until 6 months show improved growth and development

BACKGROUND

The purpose of the present study was to determine the effect of feeding nutrient-enriched preterm formula to preterm infants until 6 months' corrected age (CA) on growth and development in the first 18 months of life.

METHODS

Very low-birthweight preterm infants were fed preterm formula until term (40 weeks CA). Infants were then assigned to one of three groups and were fed term formula until 6 months' CA (group 1, n= 29); preterm formula to 3 months' CA and then term formula to 6 months' CA (group 2, n= 30); or preterm formula until 6 months' CA (group 3, n= 31). Anthropometry was performed at term, 3, 6, 9, 12, 15, and at s18 months' CA. Mental and psychomotor development were assessed using the Bayley Scales of Infant Development II at 18 months' CA.

RESULTS

Although body weight, length, head circumference and z score for CA at term in group 3 were significantly lower than those of groups 1 and 2, growth rates of these parameters were significantly higher in group 3 up to 18 months CA', as compared to groups 1 and 2. The mental developmental index and psychomotor developmental index of the Bayley test were not significantly different between the three groups.

CONCLUSIONS

Very low-birthweight preterm infants fed nutrient-enriched preterm formula until 6 months' CA demonstrated significantly improved growth rates for bodyweight, length and head circumference, and comparable mental and psychomotor development throughout the first 18 months of life.

Twelve-month neurodevelopmental outcome in preterm infants with and without intrauterine growth restriction

AIM

To evaluate the neurodevelopmental outcome at 12 months' corrected age in preterm infants with and without severe intrauterine growth restriction.

METHODS

This prospective follow-up study included 37 infants with severe intrauterine growth restriction and 36 appropriate-for-gestational-age infants born between 26 and 34 weeks. Neonatal and infant data were prospectively recorded. Infants were assessed at 12 ± 2 months' corrected age with the Hammersmith Infant Neurological Examination and the Bayley Scale for Infant Development version-II.

RESULTS

Both groups were similar in demographic characteristics and perinatal status. No significant differences in neurodevelopmental performance were found. The mental development index was 98.8 (SD 9.0) vs 98.4 (SD 13.1) (p = 0.9) and the psychomotor development index was 91.7 (SD 9.9) vs 95.5 (SD 13.4) (p = 0.2) for the study and reference groups respectively. Neurological assessment showed no significant differences between the two groups.

CONCLUSION

Although the study group showed a non-significant trend towards a lower score in the psychomotor development index than the reference group, significant differences at 12 months could not be demonstrated. IUGR infants continued to have significantly lower weight, length and head circumference at 1 year.

Developmental correlates of head circumference at birth and two years in a cohort of extremely low gestational age newborns

OBJECTIVES

To evaluate the developmental correlates of microcephaly evident at birth and at 2 years in a cohort born at extremely low gestational age.

METHODS

We assessed development and motor function at 2 years of 958 children born before the 28th week of gestation, comparing those who had microcephaly at birth or 2 years with children with normal head circumference while considering the contribution of neonatal cranial ultrasound lesions.

RESULTS

A total of 11% of infants in our sample had microcephaly at 2 years. Microcephaly at 2 years, but not at birth, predicts severe motor and cognitive impairments at 2 years. A total of 71% of children with congenital microcephaly had a normal head circumference at 2 years and had neurodevelopmental outcomes comparable with those with normal head circumference at birth and 2 years. Among children with microcephaly at 2 years, more than half had a Mental Developmental Index <70, and nearly a third had cerebral palsy. The risks were increased if the child also had cerebral white matter damage on a cranial ultrasound scan obtained 2 years previously.

CONCLUSION

Among extremely low gestational age newborns, microcephaly at 2 years, but not at birth, is associated with motor and cognitive impairment at age 2.

Two methods for estimating age of newborns in catch-up growth studies

Catch-up growth has been the subject of many studies, but whether and when infants born preterm and with low birth weight achieve normal size is controversial. One of the reasons for diverse results is likely to be the difference in how the infants' ages are calculated. The aim of this work is to analyse the occurrence and chronological distribution of compensational events of 163 infants born preterm conducted according to both chronological and corrected age. Catch-up growth was defined as the compensation of body weight values to those included between +/-1 SD in the reference system. Data were analysed using the survival analysis. Catch-up growth events were observed in greater amount for gestation-adjusted age. The correction of age allows the indication of the age, corresponding to the correct time of birth, as the time of the most rapid growth velocity. Chronological age does not allow any particular time to be distinguished as the most characteristic moment for achievement of constitutional growth. Within the whole studied period there is a similar probability of growth equalisation. A description of the morphological development of preterm infants should not be made in comparison to the postnatal reference system without correction of age, but analyses considering chronological age are necessary when the influence of gestational age is considered.

Nutrition for preterm infants after hospital discharge

Preterm infants accrue significant nutrient deficits during hospitalization, and at the time of discharge most VLBW preterm infants have moderate to severe growth failure. Infants with significant morbidities and infants with ELBW have more severe growth failure since they regain birth weight at a later age, and they gain weight more slowly. Catch-up growth accelerates after hospital discharge. The rates of catch-up growth vary according to many factors including birth weight, gestational age, parental size, adequacy of intrauterine growth, neurologic impairment, clinical course, and nutrition. Most catch-up growth occurs within the first 2 to 3 years of life; however, compensatory catch-up growth may continue into adolescence and adulthood. Despite evidence of ongoing catch-up growth, the mean growth measurements of children and adults who were born preterm and with VLBW are lower than their term-born peers. Accelerated rates of catch-up growth are associated with better neurodevelopmental outcomes. Inadequate head circumference growth, in particular, may have long-term prognostic significance for later neurodevelopment in preterm infants. Nutrient-enriched formulas that provide 22 kcal/oz are often prescribed for VLBW preterm infants after hospital discharge. Several studies have reported that preterm infants fed the enriched versus standard term infant formulas have greater rates of catch-up growth during the first year of life, including greater increases in head circumference. The nutrient-enriched formulas appear to be of particular benefit for male infants. There is less information regarding the nutrient needs of breast-fed infants after hospital discharge. However, several studies have demonstrated that preterm infants fed unfortified human milk after discharge have growth rates and bone mass that are lower than formula-fed infants during infancy. The use of fortified human milk, or alternate feedings with a nutrient-enriched formula may be useful for breast-fed infants who have delays in catch-up growth. Additional studies are needed to determine whether enriched feedings might be of particular benefit for preterm infants who are at greater risk for postnatal growth failure, including infants born SGA, or with extremely low birth weights, intrauterine growth restriction, or chronic conditions such as bronchopulmonary dysplasia. The potential effect of nutritional programming on long-term outcomes of preterm infants also requires further investigation.

Advances in nutritional modifications of infant formulas

Modifications to infant formulas are continually being made as the components of human milk are characterized and as the nutrient needs of diverse groups of infants are identified. Formulas with long-chain polyunsaturated fatty acids added in amounts similar to those in human milk have recently become available in the United States; infants fed these formulas or human milk have higher tissue concentrations of long-chain polyunsaturated fatty acids and reportedly have better visual acuity than do infants fed nonsupplemented formulas. Selenium, an important antioxidant, is present in higher concentrations in human milk than in non-fortified cow milk-based formula, and the selenium intakes of infants fed nonfortified formulas are reported to be at or below recommended levels. Blood selenium concentrations and plasma glutathione peroxidase activity are higher in infants fed selenium-supplemented formulas or human milk than in infants fed non-fortified formulas. Nucleotides and their related products play key roles in many biological processes. Although nucleotides can be synthesized endogenously, they are considered "conditionally essential." Nucleotide concentrations in human milk are higher than in unsupplemented cow milk-based formulas, and studies in animals and human infants suggest that dietary nucleotides play a role in the development of the gastrointestinal and immune systems. Formulas for preterm infants after hospital discharge are designed to meet the needs of a population in whom growth failure is common. Several studies have shown that preterm infants fed nutrient-enriched formulas after hospital discharge have higher rates of catch-up growth than do infants fed standard term-infant formulas.

Metabolic effects of infection and postnatal steroids

Optimal development of the newborn depends on rapid accretion of substrate in the neonatal period, particularly in the premature infant. Steroids and infection not only induce catabolism, but associated endogenous responses reprioritize crucial substrate to restore homeostasis. The result is a protein/energy deficit and concomitant delay in growth and development. Innovative feeding strategies and novel therapies are needed to reduce the impact of catabolism in this population.

Growth of preterm infants fed nutrient-enriched or term formula after hospital discharge

OBJECTIVE

At hospital discharge, preterm infants may have low body stores of nutrients, deficient bone mineralization, and an accumulated energy deficit. This double-blind, randomized study evaluated the growth of premature infants with birth weights <1800 g who were fed a 22 kcal/fl oz nutrient-enriched postdischarge formula (PDF) or a 20 kcal/fl oz term-infant formula (TF) from hospital discharge to 12 months' corrected age (CA).

METHODS

Infants were randomized to PDF or TF a few days before hospital discharge with stratification by gender and birth weight (<1250 g or >/=1250 g). The formulas were fed to 12 months' CA. Growth was evaluated using analysis of variance controlling for site, feeding, gender, and birth weight group. Interaction effects were also assessed. Secondary analyses included a repeated measures analysis and growth modeling.

RESULTS

One hundred twenty-five infants were randomized; 74 completed to 6 months' CA and 53 to 12 months' CA. PDF-fed infants weighed more than TF-fed infants at 1 and 2 months' CA, gained more weight from study day 1 to 1 and 2 months' CA, and were longer at 3 months' CA. There were significant interactions between feeding and birth weight group-among infants with birth weights <1250 g, those fed PDF weighed more at 6 months' CA, were longer at 6 months' CA, had larger head circumferences at term 1, 3, 6, and 12 months' CA, and gained more in head circumference from study day 1 to term and to 1 month CA. The repeated measures and growth modeling analyses confirmed the analysis of variance results. The PDF formula seemed to be of particular benefit for the growth of male infants. Infants fed the PDF consumed less formula and had higher protein intakes at several time points. Energy intakes, however, were not different.

CONCLUSIONS

Growth was improved in preterm infants fed a nutrient-enriched postdischarge formula after hospital discharge to 12 months' CA. Beneficial effects were most evident among infants with birth weights <1250 g, particularly for head circumference measurements.

Neurodevelopmental outcome of very low birth weight babies admitted to a Malaysian nursery

OBJECTIVE

To examine the prevalence and pattern of neurodevelopmental handicap at 2 years of age in very low birth weight infants (VLBW) admitted in 1993 to a level 3 Malaysian nursery.

METHODS

All VLBW babies born in the hospital or referred for neonatal care during 1993 were enrolled prospectively in the study. At 2 years of age development was assessed using the Griffiths mental scales. Neurological, hearing and visual assessments were graded into five groups according to functional handicap. Control infants were randomly selected during attendance at a primary health care clinic.

RESULTS

One hundred and fifty VLBW infants were admitted and 82 (54.6%) survived to 2 years, of whom 77 (93.9%) were assessed. The mean General Quotient (GQ) on the Griffiths Scales was 94 (15.7) for the study group and 104 (8.3) for the 60 controls. For GQ, 21 (27.3%) of the study population were 1 or more SD below the mean (18 between 1 and 2 SD and 3 > 2 SD) compared with 1 (1.6%) of the controls who was 1-2 SD below the mean. Visual impairment occurred in 2 study infants and none of the controls. There was no hearing impairment in either group. Cerebral palsy occurred in 3 (1 mild and 2 moderate-severe) of the study group and none of the controls. Functionally 18 (23.3%) of the study group had mild handicap, 1 (1.3%) moderate, 2 (2.5%) severe, 2 (2.5%) multiply severe and 54 (70.2%) were normal.

CONCLUSION

Although survival was low, overall rates of functional handicap were similar to those reported in developed countries but the proportion with moderate or severe handicap was low.

Health and developmental outcomes at 18 months in very preterm infants with bronchopulmonary dysplasia

OBJECTIVE

To determine whether very preterm infants who are oxygen-dependent at 28 days of life but not at 36 weeks' gestational age are at high risk of morbidities at 18 months.

POPULATION

A total of 217 infants born in a tertiary care center at 24 to 28 weeks' gestation in 1987 to 1992, classified into three groups: neonatal comparison group, O2 <28 days of life (n = 76); bronchopulmonary dysplasia (BPD)-1, O2 >/=28 days but not at 36 weeks' gestational age (n = 48); and BPD-2, O2 >/=36 weeks (n = 93).

OUTCOME MEASURES

Growth, persistent respiratory problems (asthma, tracheostomy, home oxygen therapy), surgery, hospitalizations, and neurodevelopmental impairments.

RESULTS

Among the three groups, no differences were found in weight, height, head circumference, or total number of days of rehospitalizations for any causes, or in rate of rehospitalizations to the intensive care unit, persistent respiratory problems, cerebral palsy, or sensory impairment. Children with BPD-2 needed more hernia repairs compared with the other two groups (comparison group: 12% vs BPD-1: 10% vs BPD-2: 30%), had more days of readmissions for respiratory problems (comparison group: 2.0 vs BPD-1: 2.0 vs BPD-2 6.3 [BPD-1 vs BPD-2]), had a lower mean developmental quotient (comparison group: 97.4 +/- 15.0 vs BPD-1: 97.9 +/- 11.6 vs BPD-2: 90.7 +/- 19.3). Intraparenchymal cerebral lesions, high family adversity, and prolonged ventilation were the most important factors influencing the developmental outcome.

CONCLUSION

Children with BPD-1 are similar in all respect at 18 months to children in the comparison group. Children with BPD-2 are similar to the other groups at 18 months in growth, general health, and neurologic outcome but differ in having a higher number of days of rehospitalizations for respiratory causes, more hernia repairs, and more developmental delays.