How does gestational age affect growth and body composition of preterm twins?

BACKGROUND: Twins experience altered growth compared to singletons. The primary aim of this study was to compare growth and body composition (BC) of twin and singleton preterm infants from birth to 3 months according to gestational age (GA). Secondary aims were to evaluate the effect of chorionicity and mode of feeding on twins' BC. METHODS: Anthropometric measurements and BC were performed at term and 3 months in preterm infants (GA < 37 weeks). Infants were categorized as: extremely, very, moderate and late preterm infants. Chorionicity was assigned as monochorionic, dichorionic or multichorionic. Mode of feeding was recorded as any human milk feeding vs formula feeding. RESULTS: Five hundred and seventy-six preterm infants were included (223 twins). Late-preterm twins were lighter and shorter at each study point; fat-free mass (FFM) was lower in these infants at each study point, compared to singletons. No differences were found between twins and singleton on the other category. Multichorionic infants had an FFM deficit compared to monochorionic and dichorionic at term, whereas no differences were found at 3 months. FFM at term was negatively associated with being twin and formula-fed. CONCLUSIONS: Twins and singletons born before 34 weeks' GA showed similar anthropometry and BC. Conversely, twin late-preterm infants showed different growth and BC compared to singletons.

Can Basic Characteristics Estimate Body Composition in Early Infancy?

OBJECTIVES: Increasing evidence demonstrates that body composition in early life contributes to the programming of health later in life in both full-term and preterm infants. Given the important role of body composition, the increased availability of easy, noninvasive, and accurate techniques for its assessment has been recommended. The aim of the present study was to identify basic characteristics and anthropometric measurements that best correlate with body composition in infants. METHODS: Anthropometric measurements and body composition assessed by air-displacement plethysmography were assessed either at birth or at term-corrected age in 1239 infants (654 full-term, 585 preterm). The associations of sex, GA (gestational age), and weight with FFM (fat-free mass) and FM (fat mass) adjusted by length (g/cm) were investigated by multiple linear regression models. Bland-Altman tests were performed, and an equation for calculating FFM was determined. RESULTS: Preterm infants exhibited increased FM and reduced FFM compared with full-term infants (477.6 ±â€Š204 vs 259.7 ±â€Š147 g and 2583 ±â€Š494 vs 2770 ±â€Š364 g, respectively). GA, male sex, and weight were positively associated with FFM (r = 0.806, P < 0.0001; 6.1 g of average bias). GA and male sex were negatively associated with FM, whereas weight was positively associated with FM (r = 0.641, P < 0.0001; 4.9 g of average bias). CONCLUSIONS: The assessment of body composition represents the criterion standard. When body composition assessment is not feasible, the equation based on sex, GA, and anthropometric measurements can be useful in predicting body composition in both full-term and preterm infants.

Postnatal catch-up fat after late preterm birth.

BACKGROUND: Late preterm birth accounts for 70% of preterm births. The aim of the study was to investigate the postnatal weight gain and weight gain composition changes in a cohort of late preterm infants. METHODS: A total of 49 late preterm infants (mean birth weight 2,496 ± 330 g and gestational age 35.2 ± 0.7 wks) underwent growth and body composition assessment by an air displacement plethysmography system on the fifth day of life, at term, and at 1 and 3 mo of corrected age. The reference group was composed of 40 healthy, full-term, breast-fed infants. RESULTS: The late preterm infants showed a Δ fat mass gain between birth and term-corrected age equal to 182%. As compared with full-term infants, at term and 1 mo of corrected age mean weight (3,396 ± 390 vs. 3,074 ± 409 g and 4,521 ± 398 vs. 4,235 ± 673 g, respectively) and percentage of fat mass (16.1 ± 4.6 vs. 8.9 ± 2.9 and 22.6 ± 4.2 vs. 17.4 ± 4.0, respectively) were significantly higher in late preterm infants, whereas no difference among groups was found at 3 mo. CONCLUSION: Rapid postnatal catch-up fat was found in these infants. Further studies are needed to investigate whether this short-term increase in fat mass may modulate the risk of chronic diseases or represent an adaptive mechanism to extrauterine life.

The indirect calorimetry in very low birth weight preterm infants: An easier and reliable procedure.

OBJECTIVES: Preterm infants are at increased risk of developing extrauterine growth restriction, which is associated with worse health outcomes. The energy needs are not well known, as the measurement of resting energy expenditure (REE) using indirect calorimetry has critical issues when applied to infants. One of the main issues is the time required to obtain reliable data owing to the difficulty in keeping infants quiet during the entire examination. Thus, the aim of this study was to define the minimum duration of calorimetry to obtain reliable data. METHODS: The volume of oxygen consumption (VO2) and the volume of carbon dioxide production (VCO2) were recorded for a mean duration of 90 consecutive minutes. REE was calculated using a neonatal prototype calculator. We extracted data regarding VO2, VCO2, and REE at 10(T1), 20(T2), 30(T3), 40(T4), and 50(T5) minutes of steady state and compared these data to those of entire steady state period. RESULTS: Twenty-six very low birth weight preterm infants were evaluated at 36.58 ± 0.99 wk corrected age. Infants were appropriate for gestational age and clinically stable without comorbidities. There were no significant differences between mean VO2 and REE at T1 (8.26 ± 1.45 mL/kg to 57.80 ± 10.51 kcal/kg), T2 (8.15 ± 1.41 mL/kg to 56.87 ± 10.05 kcal/kg), T3 (8.04 ± 1.41 mL/kg to 56.32 ± 9.73 kcal/kg), T4 (8.05 ± 1.41 mL/kg to 56.07 ± 10.28 kcal/kg), and T5 (8.06 ± 1.55 mL/kg to 57.17 ± 11.62 kcal/kg), respectively, compared to steady state (8.13 ± 1.33 mL/kg to 56.77 ± 9.34 kcal/kg). The median values of VCO2 were significantly different only when T1 data were compared with other time slots (7.02 ± 1.02 mL/kg at steady state; 7.26 ± 1.23 mL/kg at T1; 7.13 ± 1.20 mL/kg at T2; 7.02 ± 1.19 mL/kg at T3; 6.85 ± 1.16 mL/kg at T4; 6.91 ± 1.24 mL/kg at T5). CONCLUSION: Twenty consecutive minutes in steady state condition are sufficient to obtain reliable data on REE in stable, very low birth weight infants.

Determinants of breastfeeding discontinuation in an Italian cohort of mother-infant dyads in the first six months of life: a randomized controlled trial.

BACKGROUND: Among breastfeeding determinants, the marketing of breast milk substitutes might contribute to suboptimal breastfeeding rates. The aim of this study was to investigate the effect of receiving information on breast milk substitutes on breastfeeding rates. METHODS: We conducted a randomized, single-blind, controlled trial from 2012 to 2014 in a northern Italian maternity ward. We enrolled 802 Caucasian mothers who gave birth to healthy, full-term singletons with a birth weight > 2500 g and who were exclusively breastfeeding from delivery to discharge. Mothers who gave birth to infants with congenital diseases, chromosomal abnormalities, perinatal infections and/or cardio-respiratory instability and/or mothers being affected by endocrine and/or metabolic and/or gastrointestinal and/or renal diseases were excluded. Mothers were randomized to either receive (group A, n = 405) or not (group B, n = 397) written information on a breast milk substitute at discharge. Breastfeeding was promoted and supported in all mother-infant pairs equally. The mode of feeding for up to 6 months after delivery was determined by phone interview. To detect a 10% difference between groups in the discontinuation rate of exclusive breastfeeding at three months of age at 5% significance and 80% power, a total of 356 mother-infant pairs per group were needed. RESULTS: The exclusive breastfeeding prevalence was 91% and 92% at 7 days, 79% and 70% at 1 month, 75% and 66% at 2 months, 72% and 62% at 3 months, and 3% and 2% at 6 months in groups A and B, respectively. The relative risk (95% confidence interval) of exclusive breastfeeding (group A vs B) at 7 days and at 1, 2, 3 and 6 months was as follows: 0.99 (0.95-1.03), 1.12 (1.03-1.21), 1.13 (1.03-1.24), 1.15 (1.04-1.27), and 1.49 (0.62-3.61). Nutritional, lifestyle and lactational factors were the primary contributing determinants to early breastfeeding discontinuation. CONCLUSIONS: The present findings indicate that receiving written information on breast milk substitutes at hospital discharge, provided that breastfeeding support and education are offered, does not negatively affect breastfeeding rates. TRIAL REGISTRATION: NCT03208114. Registered 5 July 2017.

Protein use and weight-gain quality in very-low-birth-weight preterm infants fed human milk or formula.

Background: Nutritional management of preterm infants aims to approximate the tissue growth and body composition of a fetus of the same postmenstrual age. The adequacy of the quality of protein supply can influence the rate and the relative quality of weight gain. Objective: We investigated the protein balance according to feeding regimen and the association between human milk feeding and fat-free mass content at the term-corrected age in very-low-birth-weight preterm infants. Design: A prospective observational study was conducted. Inclusion criteria were as follows: healthy infants, gestational age ≤32 wk, birth weight <1500 g, stable clinical conditions, and feeding by mouth with human milk or formula at discharge. Infants were enrolled at hospital discharge. At enrollment, macronutrient intakes and protein balance were determined. Anthropometric measurements and body composition were also assessed. The nutritional composition of human milk was calculated by infrared spectroscopy. The protein balance was determined according to the nitrogen balance standard method. Body composition was assessed by an air-displacement plethysmography system. At the term-corrected age, anthropometry and body composition assessments were repeated. Results: Seventeen preterm infants fed fortified human milk and 15 preterm infants fed formula were enrolled. At discharge, despite similar macronutrient intakes, infants fed fortified human milk showed a higher nitrogen balance (expressed as mg · kg-1 · d-1) compared with preterm formula-fed infants (mean ± SD: 488.3 ± 75 compared with 409.8 ± 85 mg · kg-1 · d-1, P = 0.009). At term-corrected age, growth was similar in the 2 groups, whereas fortified human milk-fed infants showed a higher percentage of fat-free mass (85.1% ± 2.8% compared with 80.8% ± 3.2%, P = 0.002). Moreover, at multiple linear regression, fat-free mass content was independently associated with being fed human milk (R2 = 0.93, P < 0.0001). Conclusion: Our findings suggest that human milk feeding is associated with early fat-free mass deposition in healthy and stable preterm infants. This trial was registered at www.clinicaltrials.gov as NCT03013374.

Body composition changes in the first 6 months of life according to method of feeding.

BACKGROUND: Early feeding choices may affect long-term health outcomes. Therefore, understanding body composition changes in healthy breastfed infants has become an important research focus. OBJECTIVES: The aims of this review were to investigate the body composition changes that occur during weight loss in breastfed term newborns and to examine body composition differences between exclusively/predominantly breastfed and exclusively formula-fed infants in the first 6 months of life. METHODS: We performed a review of the existing literature using PubMed. We searched for studies published in English since January 1, 2000, that involved human infants ranging in age from birth to 6 months. We used the following MEDLINE Medical Subject Headings: ((breastfeeding) OR (infant formula)) AND ((body composition) OR (bioelectrical impedance) OR (absorptiometry, photon) OR (total body potassium) OR (isotope dilution) OR (air-displacement plethysmography)). Our search yielded 6 studies. RESULTS: Two studies reported that newborn weight loss was due to a reduction in the quantity of both fat mass and fat-free mass. Three out of 4 articles that evaluated body composition changes according to method of feeding reported no differences in body composition between exclusively/predominantly breastfed and exclusively formula-fed infants in the first 4.5 months of life. One study reported that exclusively breastfed infants at 3 months of age and exclusively breastfed boys at 6 months of age had higher fat mass contents compared to exclusively formula-fed infants. CONCLUSION: Because of the limited number of studies available, larger studies are needed to clarify the differences in body composition between exclusively/predominantly breastfed and exclusively formula-fed infants.

Nutrition and growth in infants born preterm from birth to adulthood.

Prevention of extra-uterine growth retardation is of extreme importance, as the achievement of adequate growth has been associated with a favorable neurodevelopmental outcome through childhood. In addition, as disturbances in growth that take place early in life may affect adult health, a full understanding of the growth trajectory of very-low-birth-weight infants is also advisable. This review will focus attention on the nutritional strategies proposed during hospital admission and after discharge in order to limit extra-uterine growth retardation in preterm infants. The dynamic changes that characterize growth of infants born preterm from birth up to adulthood will also be addressed.

Implementation of nutritional strategies decreases postnatal growth restriction in preterm infants.

BACKGROUND: Prevention of postnatal growth restriction of very preterm infants still represents a challenge for neonatologists. As standard feeding regimens have proven to be inadequate. Improved feeding strategies are needed to promote growth. Aim of the present study was to evaluate whether a set of nutritional strategies could limit the postnatal growth restriction of a cohort of preterm infants. METHODOLOGY/PRINCIPAL FINDINGS: We performed a prospective non randomized interventional cohort study. Growth and body composition were assessed in 102 very low birth weight infants after the introduction of a set of nutritional practice changes. 69 very low birth weight infants who had received nutrition according to the standard nutritional feeding strategy served as a historical control group. Weight was assessed daily, length and head circumference weekly. Body composition at term corrected age was assessed using an air displacement plethysmography system. The cumulative parenteral energy and protein intakes during the first 7 days of life were higher in the intervention group than in the historical group (530 ± 81 vs 300 ± 93 kcal/kg, p<0.001 and 21 ± 2.9 vs 15 ± 3.2 g/kg, p<0.01). During weaning from parenteral nutrition, the intervention group received higher parental/enteral energy and protein intakes than the historical control group (1380 ± 58 vs 1090 ± 70 kcal/kg; 52.6 ± 7 vs 42.3 ± 10 g/kg, p<0.01). Enteral energy (kcal/kg/d) and protein (g/kg/d) intakes in the intervention group were higher than in the historical group (130 ± 11 vs 100 ± 13; 3.5 ± 0.5 vs 2.2 ± 0.6, p<0.01). The negative changes in z score from birth to discharge for weight and head circumference were significantly lower in the intervention group as compared to the historical group. No difference in fat mass percentage between the intervention and the historical groups was found. CONCLUSIONS: The optimization and the individualization of nutritional intervention promote postnatal growth of preterm infants without any effect on percentage of fat mass.

Growth and fat-free mass gain in preterm infants after discharge: a randomized controlled trial.

OBJECTIVE: To investigate whether the consumption of a nutrient-enriched formula after hospital discharge determines different growth and weight gain composition in preterm infants according to intra- and extrauterine growth pattern. METHODS: Two hundred seven preterm infants were randomized at term-corrected age to receive treatment A (term formula) or B (nutrient-enriched formula) up to 6 months of corrected age, using 2 computer-generated randomization lists, 1 for adequate for gestational age (AGA) and 1 for small for gestational age (SGA) infants. Infants were weaned according to our clinical practice after 6 months' corrected age. Anthropometric parameters and body composition by an air displacement plethysmography system were assessed at term and 1, 3, and 6 months' corrected age. Anthropometric parameters were also assessed at 12 months. RESULTS: Protein intakes were higher in infants receiving treatment B than in infants receiving treatment A at each study point. There were no differences between the feeding groups in weight and length SD scores in either the AGA and SGA group through the study. The mean head circumference values were higher in AGA infants receiving treatment B than in AGA infants receiving treatment A at 6 and 12 months, whereas at 6 months, the percentage of fat mass was lower. No difference in body composition was detected among SGA infants through the study. CONCLUSIONS: This randomized controlled trial demonstrates the beneficial effect of the consumption of a nutrient-enriched formula after hospital discharge by AGA infants both in terms of head circumference growth and fat-free mass gain.