Conditional reference charts to assess weight gain in British infants

Growth monitoring in infancy is a useful tool for detecting growth disorders and failure to thrive. However, current weight charts do not monitor growth as such, they only identify infants whose weight centile is low and/or falling. A reference of conditional weight gain is described which compares an infant's current weight with that predicted from their previous weight, allowing for the fact that on average, light infants tend to grow faster than heavier infants. The reference, which expresses conditional weight gain as an SD score of centile, is based on the UK 1990 weight reference supplemented with correlation data on 223 infants from the Cambridge Infant Growth Study measured regularly between 4 weeks and 2 years of age. The reference is validated with data on 727 infants from the Newcastle Regional Health Authority database. The conditional reference provides a valid assessment of the weight gain of British infants, over time periods of four or more weeks, throughout the first two years of life.     

Postnatal weight loss in term infants: what is "normal" and do growth charts allow for it?

BACKGROUND: Although it is a well known phenomenon, limited normative data on neonatal weight loss and subsequent gain are available, making it hard to assess individual children with prolonged weight loss. OBJECTIVE: To establish, using data from a large prospective population based cohort study, norms and limits for postnatal weight loss and its impact on current growth reference charts. METHOD: A cohort of 961 term infants were recruited at birth and followed using parental questionnaires and community nursing returns. Routine weights were collected for half the cohort at 5 days and for all at 12 days and 6 weeks. RESULTS: Less weight loss was seen than the 3-6% suggested by previous studies, but one in five infants had not regained their birth weight by 12 days. Those lightest at birth showed least weight loss. Twenty six (3%) children had more than 10% weight loss, but none showed evidence of major organic disease. Actual weights in the first fortnight are half to one centile space lower than growth charts suggest, while birthweight centiles for children born at 37 weeks were two centile spaces lower. CONCLUSIONS: Neonatal weight loss is brief, with few children remaining more than 10% below birth weight after 5 days. Growth charts are misleading in the first 2 weeks, because they make no allowance for neonatal weight loss.     

Catch up Growth in Preterm Infants

Seventy-one surviving infants were followed up from birth to 24 weeks of postnatal age. Their mean gestational age was 32 weeks with a range of 26–36 weeks and a standard deviation of 2.1 weeks. Their mean birth weight was 1.805 kg with a range of 0.675–2.5 kg and a standard deviation of 0.408 kg. Their weights, lengths and head circumferences were measured at birth, 6, 12 and 24 weeks. Curves for the mean weight, length and head circumference were produced and superimposed on the available intrauterine and extra-uterine growth charts. The growth curves of the preterm infants did not show the flattening noted in the intrauterine curves towards term. The curve of the mean weight of the preterm infants started at the 50th centile for Gairdner & Pearson (1971) at birth to drop below that shortly after birth. At 40 weeks of postconceptional age the mean weight curve of preterm infants crossed the 50th centile and continued above it to reach the 90th centile at 60 weeks. The curves of mean length and head circumference started below the 50th centile at birth and crossed it at 40 weeks and continued above it to approach the 90th centile at 60 weeks. Growth velocity was calculated as a relative gradient using the straight line equation (y=a+bx), where y is the weight, length or head circumference, and x is the independent variable and here it is the group mean of the parameter at the corresponding ages. Catch up growth is taken as a relative gradient significantly greater than one. The first 24 weeks of postnatal life are defined as a period of catch up growth with the first 8 weeks as an interval of maximum head velocity.     

Comparison of the use of Tanner and Whitehouse, NCHS, and Cambridge standards in infancy

The British (Tanner and Whitehouse) and American (National Center for Health Statistics, NCHS) growth standards are widely used internationally, although the data are now over 30 years old. Routine weight data was retrieved from the child health records of a complete annual cohort of 3418 children aged 18-30 months to test the validity of these standards for modern infants. Compared with the Tanner and Whitehouse standards, Newcastle children rose initially and then fell a mean of 0.7 SDs between 6 weeks and 18 months, resulting in a threefold difference in the proportion of children below the 3rd centile at different ages. NCHS standards showed a similar pattern. When compared with modern standards from the Cambridge growth study, there was a much closer match, although Newcastle children showed a slight gain by the age of 1 year. Existing standards for weight introduce inaccuracy into the estimation of centile position in the early months of life. As both standards show similar problems this probably represents a real secular change due to changes in infant nutrition. These findings support the need to develop new national growth reference standards.     

Comparison of the use of Tanner and Whitehouse, NCHS, and Cambridge standards in infancy.

The British (Tanner and Whitehouse) and American (National Center for Health Statistics, NCHS) growth standards are widely used internationally, although the data are now over 30 years old. Routine weight data was retrieved from the child health records of a complete annual cohort of 3418 children aged 18-30 months to test the validity of these standards for modern infants. Compared with the Tanner and Whitehouse standards, Newcastle children rose initially and then fell a mean of 0.7 SDs between 6 weeks and 18 months, resulting in a threefold difference in the proportion of children below the 3rd centile at different ages. NCHS standards showed a similar pattern. When compared with modern standards from the Cambridge growth study, there was a much closer match, although Newcastle children showed a slight gain by the age of 1 year. Existing standards for weight introduce inaccuracy into the estimation of centile position in the early months of life. As both standards show similar problems this probably represents a real secular change due to changes in infant nutrition. These findings support the need to develop new national growth reference standards.     

Implications of adopting the WHO 2006 Child Growth Standard in the UK: two prospective cohort studies.

BACKGROUND: The WHO 2006 Child Growth Standard is based on data from international optimally nourished breastfed infants from birth to age 5 years. OBJECTIVE: To assess the potential effect of its use on weight and growth monitoring of UK children. PARTICIPANTS: Full-term members of two population-based UK birth cohorts: the Children in Focus sub-cohort of the Avon Longitudinal Study of Parents and Children (ALSPAC) (n = 1335) and the Gateshead Millennium Baby Study (GMS; n = 923). DESIGN: Growth data from birth to 5 years were converted into z-scores relative to the WHO 2006 standard. RESULTS: Compared with the WHO standard, both UK cohorts had higher birth weights (mean z-scores: GMS, 0.17; ALSPAC, 0.34) and ALSPAC had higher birth lengths. After birth, length showed a good fit at all ages. By 2-4 months, both cohorts were similar in weight to the WHO median (mean WHO weight z-score at 4 months: GMS, 0.01; ALSPAC, -0.07), but thereafter the UK cohorts were heavier (mean WHO weight z-score at 12 months: GMS, 0.57; ALSPAC, 0.65). At age 12 months, the risk of being classified as underweight (weight <2nd centile) was considerably lower according to the WHO standard than by the UK 1990 Growth Reference (RR = 0.15, 95% CI = 0.07 to 0.32), and the risk of being classified as obese at 4-5 years (body mass index >98th centile) was slightly increased (RR = 1.35, 95% CI = 1.02 to 1.78). CONCLUSIONS: Adoption of the WHO 2006 Growth Charts would set a markedly lower standard of weight gain beyond the age of 4 months for UK infants and could support efforts to avoid future childhood obesity. However, the WHO standard is not representative of size at birth in the UK.     

Nutritionally regulated hormonal factors in prolonged postnatal growth retardation and its associated adverse neurodevelopmental outcome in extreme prematurity

Recent published data show that at hospital discharge, most infants born at <30 weeks of gestation would not achieve the median birth weight of the reference fetus at the same postconceptional age, and many would be less than the 10th centile. Estimating from the current recommendations of calorie and protein intakes, these infants accrue large deficits in intakes of protein and calorie during the first weeks of life. Postnatal growth retardation over a prolonged period of time is related to neurodevelopmental delays. While a total energy intake of 120 kcal/kg/day has generally been considered adequate, protein requirement in low gestation infants remains a matter for debate. Increasing the dietary protein:calorie ratio has previously been proposed as a strategy to enhance growth and to achieve a body composition similar to that of the reference fetus. Previous study data reveal that serum insulin-like growth factor I (IGF-I) concentration is positively correlated with protein intake, and nitrogen retention, in turn, is positively correlated with serum IGF-I concentration. Remarkably, elevated serum growth hormone but low serum IGF-I concentrations have been reported in low gestation infants and in infants with intrauterine growth retardation, suggesting IGF-I being a nutritionally regulated hormonal factor in the postnatal growth retardation. As neurodevelopment in extreme prematurity is likely affected by multiple factors, we hypothesize that a combined strategy of the previously proposed hormonal supplement with hydrocortisone and tri-iodothyronine together with increased dietary protein intake (progressively increasing from 1.5 g/kg/day intravenously administered amino acids immediately after birth, then 3.6 g/100 kcal at approximately 125 kcal/kg/day when enterally fed till the infant reaches a body weight of >or=1.8 kg and at >or=50th centile weight of the reference fetus at the same postconceptional age) would likely be synergistic and more effective in improving neurodevelopmental outcome.     

Long-Term Growth in Small-for-Date Children

Fitzhardinge, P.M. and Inwood, S. (Mount Sinai Hospital, Toronto, Ontario, Canada). Long-term growth in small-for-date children. Acta Paediatr Scand [Suppl] 349: 27, 1989.
The growth patterns of 158 infants with significant intrauterine growth retardation (IUGR) were studied for the first 2 years of life. Eighty-four infants were born after 36 completed weeks. All these full-term infants survived; complete follow-up data were obtained for 78. Acceleration of growth in weight began soon after birth and continued for an average of 6 months. Acceleration of linear growth began somewhat later, but was limited to the first 9 months. Twenty-three infants (29%) were still below the 5th centile for both weight and height by 2 years of age. There was a negative correlation between the neonatal ponderal index and length at 18 months for females only. Seventy-four infants were born prematurely, before 37 weeks'gestation. Mortality in this group was 18% and complete follow-up data were obtained for 49 of the 61 survivors. Birth weight was regained on average at 11 days; accelerated weight velocity began 4–6 weeks before the expected date of delivery (term date). The potential for catch-up growth lasted up to 9 months after the term date. By 18 months, however, 44% of these pre-term infants were still below the 5th centile for weight. Size at 18 months post-term was correlated with weight at the term date and length at 3 months post-term, but not with the degree of IUGR or with the ponderal index.     

What is a normal rate of weight gain in infancy?

We have retrieved weights from the Child Health records of an annual cohort of 3418 full-term children, aged 18–30 months in order to define a lower limit of normality for weight gain for both clinical and research purposes. There was a strong tendency for children at the extremes of the distribution to move inwards towards the average: only 26% of those below the 3rd centile for weight at six weeks were still below it at one year. We describe a method based on conditional standards to correct for this "regression to the mean" and produce a measure of the discrepancy between a child's predicted and actual growth: the "thrive index". The value of the thrive index below which only a minority of children fell provided a lower threshold for normality. While most children below the 3rd centile for weight at 9–24 months of age also had subnormal weight gain, 41 % of those with subnormal weight gain had not fallen below the 3rd centile.     

Weight reference charts for British long-term breastfed infants

Aim: To produce a modification of the British 1990 weight reference reflecting the growth of long-term breastfed infants. Methods: 120 infants from the Cambridge Infant Growth Study fed breast milk (with no formula) for at least 24 wk, with solids introduced at a mean age of 15 wk, were weighed every 4 wk from birth to 52 wk. Weights were converted to standard deviation scores (SDS) for gender and age post-term based on the revised British 1990 reference, averaged and smoothed across age, and then converted back to weights to provide modified median weight curves by gender. Other centile curves were constructed assuming the same variability and skewness by age as for the British reference. Results: Long-term breastfed infants were slightly heavier than the reference at birth and crossed centiles upwards to reach #0.3 SDS at 2 mo, but subsequently crossed centiles downwards to 30.2 SDS by 12 mo. Conclusion: The British 1990 reference, although better than previous growth standards, reflects the growth of long-term breastfed infants only imperfectly, with mean weight falling by 0.5 SDS from 2 to 12 mo. The provision of breastfeeding-specific centiles, either as a transparent overlay or as an alternative chart, should be useful for professionals and parents to monitor the weight of long-term breastfed infants.     

Weight gain and sudden infant death syndrome: changes in weight z scores may identify infants at increased risk.

AIMS: To investigate patterns of infant growth that may influence the risk of sudden infant death syndrome (SIDS). DESIGN: Three year population based case control study with parental interviews for each death and four age matched controls. Growth was measured from prospective weight observations using the British 1990 Growth Reference. SETTING: Five regions in England (population greater than 17 million, more than 470 000 live births over three years). SUBJECTS: 247 SIDS cases and 1110 controls. RESULTS: The growth rate from birth to the final weight observation was significantly poorer among the SIDS infants despite controlling for potential confounders (SIDS mean change in weight z score (deltazw) = -0.38 (SD 1.40) v controls = +0.22 (SD 1.10), multivariate: p < 0.0001). Weight gain was poorer among SIDS infants with a normal birth weight (above the 16th centile: odds ratio (OR) = 1.75, 95% confidence interval (CI) 1. 48-2.07, p < 0.0001) than for those with lower birth weight (OR = 1. 09, 95% CI 0.61-1.95, p = 0.76). There was no evidence of increased growth retardation before death. CONCLUSIONS: Poor postnatal weight gain was independently associated with an increased risk of SIDS and could be identified at the routine six week assessment.     

Growth curves from birth to 6 years of age: growth in weight, height and cranial circumference according to sex]

The growth supervision of children using growth curves is a widespread and useful tool in general pediatric practice. In France the latest reference curves are rather ancient, therefore it seemed to us interesting to re-examine some growth parameters and to compare them to the current reference data. PATIENTS AND METHODS: The studied sample was composed of 7,000 children from the Rh?ne-Alpes region in France who were seen for a school health check-up. Anthropometric measurements (35,000) related to weight, height and cranial circumference of these children aged from 0 to 6 were selected from their health booklets. Centile curves for these three variables were drawn from these measurements using the LMS method, which is specifically suited to these types of data. RESULTS: If height and cranial circumference can be considered as normally distributed, weight is markedly skewed to the right, reflecting a high prevalence of children with heavy weight. Comparison with current references data shows more or less similar results for weight, height and cranial circumference: the medians and the 2.5 centile are constantly higher in our sample than those of the reference data (the discrepancy increasing with age). The differences are more important regarding the part of the distribution which concerns the highest values: overall, the 90th centile of our distribution corresponds rather closely to the 97.5th one of the current reference data. Thus, at 6 years of age, the 97.5th centile of the reference weight distribution for girls is 23,400 kg, while it is estimated at 27,770 kg in our sample. One should take in account the different characteristics of the two studies to interpret these differences. CONCLUSION: The aim and use of such growth curves is discussed, together with recent computer applications in this field.     

Influence of folic acid on birthweight and growth of the erythroblastotic infant. III. Effect of folic acid supplementation.

Seventeen infants with severe (14) or moderately severe (3) erythroblastosis were given daily oral supplements of 2-5 or 5 mg folic acid from day 16 (average) to 3-2 months (average). Their rate of weight gain, expressed as weight centiles, was followed for 1 year and was compared with that of a very similar group of 34 erythroblastotic infants without folic acid supplements. By the end of the 4th month, just after stopping additional folate intake, the median centiles for weight had risen from the 40th to the 80th centile, while in the untreated control group they rose during this period from the 35th to the 50th centile. During the second half of the year both groups declined in weight centiles, the ''treated'' group ending up at the 50th centile for weight, while the control group fell to the 25th.     

Weight gain and sudden infant death syndrome: changes in weight z scores may identify infants at increased risk

AIMS—To investigate patterns of infant growth that may influence the risk of sudden infant death syndrome (SIDS).DESIGN—Three year population based case control study with parental interviews for each death and four age matched controls. Growth was measured from prospective weight observations using the British 1990 Growth Reference.SETTING—Five regions in England (population greater than 17 million, more than 470 000 live births over three years).SUBJECTS—247 SIDS cases and 1110controls.RESULTS—The growth rate from birth to the final weight observation was significantly poorer among the SIDS infants despite controlling for potential confounders (SIDS mean change in weight z score (δzw) = ?0.38 (SD 1.40) v controls = +0.22 (SD 1.10), multivariate: p < 0.0001). Weight gain was poorer among SIDS infants with a normal birth weight (above the 16th centile: odds ratio (OR) = 1.75, 95% confidence interval (CI) 1.48-2.07, p < 0.0001) than for those with lower birth weight (OR = 1.09, 95% CI 0.61-1.95, p = 0.76). There was no evidence of increased growth retardation before death.CONCLUSIONS—Poor postnatal weight gain was independently associated with an increased risk of SIDS and could be identified at the routine six week assessment.     

Growth and very low birth weight.

Information on the likelihood of catch up growth in poorly grown very low birthweight children is sparse. The centiles for weight, height, and head circumference were recorded at both 2 and 5 years of age for 135 very low birthweight children and 42 normal birthweight children. At both ages significantly more children of very low birth weight were under the 10th centile for weight and height. Children of birth weight under 1000 g were more often under the 10th centile for weight at 5 years compared with those of birth weight 1000-1500 g. Mean incremental weight gain between 2 and 5 years was significantly less for very low birthweight children. Mean increment in weight from 2 to 5 years was less for very low birthweight children who had been under the 10th centile for weight at 2 years; children who had been under the 10th centile for height also had lower mean height increments. The growth centiles achieved by 2 years of age were useful predictors of poor growth at 5 years, with perinatal data of marginal importance. Only six of 43 (14%) children with a weight at 5 years of age under the 10th centile were small for gestational age at birth. Very low birthweight children who had a weight or height under the 10th centile at 2 years of age usually remained in this category at 5 years with no evidence of catch up growth.     

The influence of maternal socioeconomic and emotional factors on infant weight gain and weight faltering (failure to thrive): data from a prospective birth cohort

Aims

To study the influence of maternal socioeconomic and emotional factors on infant weight gain and weight faltering (failure to thrive) in the first year of life.

Methods

The Gateshead Millennium Baby Study is a population birth cohort in northeast England studied prospectively from birth, via parental questionnaires and a health check aged 13 months. Data were collected on maternal education, deprivation, eating attitudes, and depression, using the Edinburgh Post Natal Depression Scale (EPDS) at 3 months. Weight gain was assessed using change in weight SD score, conditional on birth weight (Thrive Index); weight faltering was defined as conditional weight gain below the 5th centile.

Results

Of 923 eligible infants born at term, 774 (84%) had both weight and questionnaire data. Replicating a previous finding, both the highest and the lowest levels of deprivation were associated with weight faltering; this was independent of the type of milk feeding. No relation was found with maternal educational status. Maternal eating restraint was unrelated to weight gain. Infants of mothers with high depression symptom scores (EPDS >12) had significantly slower weight gain and increased rates of weight faltering up to 4 months (relative risk 2.5), especially if they came from deprived families, but by 12 months they were no different from the remainder of the cohort.

Conclusions

In this setting, social and maternal characteristics had little influence on infants'' weight gain, apart from a strong, but transient effect of postnatal depression.     

Lactational capacity of marginally nourished mothers: infants' milk nutrient consumption and patterns of growth

The consumption of human milk by 58 Bangladeshi infants of marginally nourished mothers was measured during longitudinal studies. Daily milk consumption, as estimated by test weighing, and intakes of energy and protein, as calculated from the measured concentrations of macronutrients in the milk, were related to infant body weight, to internationally recommended intakes of these nutrients, and to the infants' patterns of physical growth. Each of the milk variables, when related to infant body weight, declined significantly with increasing (log) infant age (P less than .001). The average consumption of energy and protein was less than current recommendations at all ages. Nevertheless, the average growth of the Bangladeshi infants approximated the fifth centile of the US National Center for Health Statistics during the first 4 months of life. By the fourth month, however, the weight increments of more than half the infants (79%) were less than the reference data. The intakes of energy and protein by individual infants less than 90 days of age were related to their patterns of growth. There were significant positive relationships between the change in Z score weight-for-age and weight-for-length and the consumption of breast milk energy (kilocalories per kilogram of body weight per day) and protein (grams per kilogram per day). Consumptions of 86.5 kcal/kg/d and protein 1.48 g/kg/d were associated with a nonchanging Z score weight-for-age. Thus, intake of these amounts of nutrients permitted weight gain comparable to the reference population but did not permit recovery from the existing relative weight deficits.     

The effect of perinatal risk factors on growth in very preterm infants at 2 years of age: the Leiden Follow-Up Project on Prematurity

OBJECTIVE: To describe growth in infants <32 weeks GA. To assess the relationship between growth and perinatal factors (like intrauterine growth retardation and the postnatal use of dexamethasone) and neurodevelopmental outcome. DESIGN: Regional, prospective study in two health regions in the Netherlands. Part of the Leiden Follow-Up Project on Prematurity (LFUPP). PATIENTS: 196 live born infants with GA <32 weeks. METHODS: At two years corrected age length, weight and head circumference of 160 of 196 surviving infants (82%) were evaluated. Standard Deviation Scores were calculated and means were compared to Dutch growth references. Mean SDS for length was corrected for the mean SDS for target height. Birth weight (BW)-SDS for gestational age (GA) was calculated according to Swedish references. RESULTS: Length, weight and weight-for-length were equally impaired in both sexes at two years in premature infants compared to Dutch growth charts. Catch-up in length and weight occurred mostly in the first year of life. Intrauterine growth retardation was associated with impairment of all growth parameters. The use of postnatal dexamethasone was associated with shorter length, lower weight, lower weight for length and smaller head circumference; this effect remained after correction for GA, BW and BW-SDS. Growth retardation (length and weight) was associated with an abnormal neurologic examination; smaller head circumference also with mental and psychomotor delay. CONCLUSION: Growth at two years corrected age in children born <32 weeks is impaired. Postnatal dexamethasone is associated with impairment of all growth parameters including head circumference, which may be a significant contributing factor for abnormal neurodevelopmental outcome.