Early postnatal growth in preterm infants

Changes in weight of 50 preterm infants (gestational age 32.7 +/- 0.3 weeks, birthweight 1772 +/- 49 g) were studied during the period of the 0-4 postnatal weeks. Intrauterine weight gain of fetuses with equivalent gestational age, weight percentile position and sex was calculated and used as a control. Study infants achieved significantly less weight by age of 4 weeks (116.2 +/- 1.2%) than it could have been expected theoretically (144.7 +/- 1.0%). Growth performance did not correlate significantly with calorie intake, but was closely related with gestational age.     

Early postnatal growth evaluation in full-term,preterm and small-for-dates infants

Postnatal growth patterns of weight, length/height and head circumference in full-term (FTI), preterm (PTI) and small-for-dates (SFDI) infants, are described by using distance and velocity data together with the concept of growth per unit of body weight. The study was performed in 112 healthy Caucasian infants, of a similar socioeconomic status, in Montevideo, Uruguay.Median growth velocity (MGV) and median growth velocity per unit (MGVU) of body size are defined. The authors stress that: (a) growth velocity is related to body mass, (b) a useful evaluation of growth is made by using two consecutive measures with a certain time interval independently of birthweight and gestational age, and (c) expressing growth per day per unit relates well to daily nutritional and other requirements.     

Water, energy and early postnatal growth in preterm infants

Non-invasive methods, including stable isotope techniques, indirect calorimetry, nutritional balance and skinfold thickness, have given a new insight into early postnatal growth in neonates. Neonates and premature infants in particular, create an unusual opportunity to study the fluid and metabolic adaptation to extrauterine life because their physical environment can be controlled, fluid and energy balance can be measured and the link between metabolism and the energetics of their postnatal growth can be assessed accurately. Thus the postnatal time course of total body water, heat production, energy cost of growth and composition of weight gain have been quantified in a series of "healthy" low-birth-weight premature infants. These results show that total body water is remarkably stable between postnatal days 3-21. Energy expenditure and heat production rates increase postnatally from mean values of 40 kcal/kg/day during the first week to 60 kcal/kg/day in the third week. An apparent energy balance deficit of 180 kcal/kg can be ascribed to premature delivery. The cost of protein metabolism is the highest energy demanding process related to growth. The fact that nitrogen balance becomes positive within 72 h after birth places the newborn in a transitional situation of dissociated balance between energy and protein metabolism during early postnatal growth: skinfold thickness, dry body mass and fat decrease, while there is a gain in protein and increase in supine length. This particular situation ends during the second postnatal week and soon thereafter the rate of weight gain matches statural growth. The goals of the following review are to summarize data on total body water and energy metabolism in premature infants and to discuss how they correlate with physiological aspects of early postnatal growth     

Fetal growth and postnatal growth failure in very-low-birthweight infants

Aim: To determine in a cohort of very-low-birthweight (VLBW) infants the incidence of postnatal growth failure and the influence of intrauterine growth and neonatal morbidities on the risk for severe postnatal growth failure (PNGF). Methods: The study was based on analysis of data from the Israel Neonatal Network database on VLBW infants born between 1995 and 2001. Z-score was determined for weight at birth and discharge, and severe PNGF was defined as a decline in z-score of greater than 2. Univariate analysis and multi-linear regression determined the effect of fetal growth and neonatal morbidities on the risk for severe PNGF. Results: Severe PNGF occurred in 10.6% of the cohort. The mean±SD birthweight (BW) z-score was -0.59±0.74, decreasing to -1.67±0.77 at discharge. The incidence of severe PNGF increased significantly with decreasing BW and gestational age. Each 1-unit increase in z-score BW was associated with a 2.37-fold increased risk for severe PNGF. Severe respiratory distress syndrome, patent ductus arteriosus, sepsis, necrotizing enterocolitis, and bronchopulmonary dysplasia were associated with severe PNGF.

Conclusion: Severe PNGF among VLBW infants was markedly influenced by intrauterine growth as well as major morbidities. In the assessment of postnatal growth among VLBW infants, growth status at birth should be considered.     

Early postnatal hypoglycaemia in newborn infants of diabetic mothers

This study found that early postnatal hypoglycaemia was mainly induced by foetal hyperinsulinaemia, in close relation to maternal hyperglycaemia. even in well-controlled pregnancies of 59 mothers with insulin-treated diabetes mellitus, 29 with insulin-dependent diabetes mellitus and 30 with gestational diabetes mellitus. Ten of the newborn children (17%) had a blood glucose concentration below 1.0mmol 1^-1 at 2h postnatally. Cord insulin-like growth factor-1 or glucagon concentrations were not related to the early decline of blood glucose.     

Bronchopulmonary dysplasia and postnatal growth in extremely premature black infants

Bronchopulmonary dysplasia (BPD) may adversely affect the postnatal growth of the extremely premature infant; however, most studies have not controlled for birth weight. We studied 90 Black premature infants (mean birth weight 989 +/- 148 g). Weight was recorded biweekly until discharge and at 4, 8, and 12 months of age corrected for prematurity. Infants with BPD (N = 23) were contrasted with infants without BPD (N = 67). Data were modeled using the Count model: Stage I birth to term and Stage II term to 12 months. Birth weight was considered part of growth beginning in utero and multivariate analyses were used to control for BPD, gestational age, duration of hospitalization and socioeconomic status. After adjustment for birth weight, BPD did not explain the growth pattern. A lower gestational age was associated with a slower establishment of steady growth (P less than 0.01), while an increased duration of hospitalization was associated with a lower growth rate (P less than 0.05). Growth in stage II was not explained by study variables. 'Catch-up' growth was seen in both infants with and without BPD. We conclude that differences in growth among infants with BPD are mainly attributable to birth weight. We speculate that poorer growth may be seen in a sub-group of infants with severe BPD.     

Early postnatal changes in intracranial arterial blood flow velocities in term infants

A range-gated Doppler technique was used to assess intracranial arterial blood flow velocity changes in 20 healthy term infants during the first 3 days after birth. Systolic, diastolic, and mean flow velocity decreased during the first 30 min after birth whereas arterial pressure and heart rate did not change. Mean flow velocity did not change from 30 min to 72 h of life, although systolic and diastolic flow velocity changed in opposite directions. Systolic flow velocity increased to 2 h of age and thereafter decreased. Diastolic flow velocity decreased to a minimum value at 2 h and thereafter increased to 24 h of age. These flow velocity changes suggest an initial decrease in cerebral perfusion, followed by a constant cerebral blood flow during normal circulatory transition after birth.     

Evaluation of postnatal weight growth in very low birth weight infants

There is general agreement about the need for longitudinal studies of very low birth weight infants (VLBWI) to evaluate their postnatal growth and to generate distance and velocity charts that allow neonatologists and pediatricians to detect earlier whether a child is not growing adequately. There are no satisfactory growth charts for VLBWI. We analyzed the weight growth of 262 VLBWIs from birth to 2 years of corrected age. Individual growth profiles were fitted with a 7-constant exponential-logistic function suitable for modelling weight growth pattern. After a postnatal weight loss, all VLBWIs showed a late neonatal peak of velocity between the seventh and 21st weeks; the large majority of them also experienced an early neonatal peak between the second and the sixth weeks. Small-for-gestational-age VLBWIs with major morbidities grew less than reference appropriate-for-gestational-age VLBWIs without major morbidities: at 2 years, the difference in weight was about 860 g. The more severe growth impairment in VLBWIs with major morbidities was almost entirely due to the reduced height of the late neonatal peak of velocity. The mathematical function used in this study is expected to be a useful tool to trace model-based longitudinal distance and velocity charts specific for VLBWIs. Moreover, this function also could be used to evaluate to what extent different pathological conditions or nutritional and medical care protocols affect growth kinetics.     

Early growth faltering in healthy term infants predicts longitudinal growth

Background

Early growth monitoring may not identify infants at-risk for later growth faltering because it is difficult for the provider to recognize how large of a negative shift might be problematic.

Aim

The aim of this study was to determine whether a slowing in early weight-for-age could be used to identify children at increased risk of later growth faltering.

Methods

Longitudinal data for infants aged birth to two years were analyzed for 1978 healthy, term infants born between 1999-2001. Logistic regression techniques were used to determine whether a negative change in weight-for-age, across well-child visit intervals, can identify infants at risk for growth faltering.

Results

The period prevalence of underweight was 24%. The odds ratio (OR) for infants with a negative shift in z-scores ≥− 0.85 between four and six months was 2.4 (95% CI 1.5, 3.9) compared to those without this shift, holding birth weight constant. Sensitivity analyses revealed that the model was significant when either the 2000 CDC growth charts (p < 0.0001) or the 2006 WHO growth charts (p < 0.0001) were used as the reference, although the prevalence of underweight was lower (14.7%) when the 2006 WHO growth charts were the reference.

Conclusion

The findings support the hypothesis that a downward shift in weight-for-age of this magnitude during early infancy when well-child visits are most frequent can be used to identify children at risk of later poor growth.     

宫内发育迟缓早产儿生后生长迟缓对早期神经发育的影响

目的 探讨宫内发育迟缓(IUGR)早产儿生后生长迟缓对早期神经发育的影响。方法 回顾性分析2008 年5 月至2012 年5 月出生并定期随访至校正胎龄6 个月的171例早产儿的临床资料,其中IUGR早产儿40 例,早产适于胎龄儿(AGA)131 例。比较两组校正胎龄40 周、3个月、6个月的生长迟缓率及校正胎龄3 个月、6 个月时的神经发育情况。神经发育采用Gesell发育量表评估。结果 IUGR 组校正胎龄40 周、3个月、6个月的生长迟缓率均明显高于AGA 组;校正胎龄3 个月时Gesell 各项发育商(大运动、精细动作、语言、适应性及个人社交)均低于AGA 组;校正胎龄6 个月时,IUGR组精细动作及语言发育商低于AGA组,但两组大运动、适应性及个人社交发育商比较差异已无统计学意义。IUGR组6月龄时体重追赶落后的患儿各项发育商均明显低于追赶理想的IUGR 和AGA 患儿。结论 IUGR早产儿生后早期的生长迟缓可对早期神经发育产生不良影响。     

Early postnatal weight gain: comparisons between Asian and white Caucasian infants

Little is known about the early weight gain of British born Asian babies. This study sets out to compare weight gain of 34 healthy Asian term babies with 34 white Caucasian babies over the first two months of life. The Asian infants were lighter at birth but their rate of weight gain did not differ significantly from their white Caucasian counterparts. These findings offer indirect support for the hypothesis that the smaller size at birth of Asian babies is not due to intrauterine growth retardation. Had this occurred a greater weight gain indicating ‘catch-up’ growth would have been expected.     

Reduction in postnatal cumulative nutritional deficit and improvement of growth in extremely preterm infants

Aim: To evaluate the influence of gestational age (GA) on cumulative nutritional deficit and postnatal growth in extremely preterm (EPT) infants after optimizing nutritional protocol as recently recommended. Methods: A prospective, nonrandomized, observational study in extremely preterm (EPT, <28 weeks) and very preterm (VPT, 28–30 weeks) infants. Results: Eighty‐four infants were included (BW: 978 ± 156 g, GA: 27.8 ± 1.3 weeks). Cumulative nutritional deficit increased during first week of life to ?290 ± 84 and ?285 ± 117 kcal/kg and ?4.2 ± 3.1 and ?4.8 ± 3.9 g/kg of protein in EPT and VPT groups, respectively. After 6 weeks, only cumulative energy deficit in EPT group remained significant (p < 0.05) even when 96% of theoretical energy intakes were provided. Weight z score decreased during first 3 days in average with initial weight loss, and then, the z score increased during the first 6 weeks of life in the majority (75%) of infants. Cumulative protein deficit during the first week of life was the major determinant of the postnatal growth during the first 6 weeks of life. Conclusion: Cumulative nutritional deficit may be drastically reduced in both EPT and VPT infants after optimizing nutritional policy during the first weeks of life, and the postnatal growth restriction could even be prevented.     

Growth charts for monitoring postnatal growth at NICU of extreme preterm-born infants

Aim: To provide growth charts for clinical monitoring of extra‐uterine growth from birth to full‐term age, in infants born before 26 weeks of gestation, hospitalized at neonatal intensive care unit (NICU), and compare it to the commonly used Swedish preterm birth‐size reference. Methods: This retrospective longitudinal cohort comprised all infants born before 26 + 0 weeks of gestation and surviving to full‐term age (n = 162), admitted to the NICU, Karolinska Hospital during the period January 1990 to December 2002. Body weight was recorded daily, head circumference (HC) weekly and length twice a month. Results: Birth weight (BW), length and HC showed a normal distribution without significant gender difference. The majority of the infants showed a pronounced postnatal growth restriction for all growth variables with increasing deviation from the reference with age. The mean initial weight loss was 16% with nadir at 6 days of age and a mean time to regain BW of 18 days. At discharge from NICU, 75% of those initially appropriate for gestational age infants were below –2 standard deviation scores for at least one of the body size variables. Conclusion: The poor extra‐uterine growth pattern points to the need of growth curves for extra‐uterine growth of extremely premature infants.