Proportionality Changes in the First Year of Life; the Influence of Weight for Gestational Age at Birth

ABSTRACT. Data on 55 small-for-gestational age (SGA), 56 average-for-gestational age (AGA) and 55 large-for-gestational age (LGA) infants whose growth had been monitored regularly from birth to 12 months are presented. SGA head-chest ratios were high at birth; but by 6 months they were very similar to AGA ratios, with values just below unity. Head-length ratios showed a steady decrement; SGA infants having the highest and LGA infants the lowest values at all ages. Chest-length ratios showed little change up to 6 months, with a steady decrease thereafter. Stem-stature ratios showed a similar pattern; and were confined within a narrow margin from 6 months onwards. These changes seem to be target orientated. We suggest the goal is that proportionality which enables the infant to attain the upright stature; and thus to sit, stand and walk at the appropriate time.     

Longitudinal investigation of the relationship between breast milk leptin levels and growth in breast-fed infants

BACKGROUND: It has been shown that leptin is present in breast milk and human mammary epithelial cells are able to synthesize leptin. It has been suggested that leptin in human milk might be involved in the regulation of postnatal nutrition and growth. AIMS: To investigate whether there is a relationship between leptin levels in human milk and weight gain in the postnatal period and to compare variations of milk-borne maternal leptin concentrations for small for gestational age (SGA), large for gestational age (LGA) and appropriate for gestational age (AGA) infants. INFANTS AND METHODS: Forty-seven healthy lactating women aged from 17-38 years and their infants were included in the study. The infants were separated into three groups according to birth weight as SGA (n = 11), LGA (n = 14) and AGA (n = 22). All infants were fed with breast milk during the study period. Anthropometric measurements were performed on the 15th day of life and at 1, 2, and 3 months of age, and the body mass index (BMI) of the infants' mothers was calculated. Breast milk leptin levels were analyzed by radioimmunoassay. RESULTS: Breast milk leptin levels were found reduced in the SGA group and increased in the LGA group compared to the AGA group at 15 days of life (13.4 +/- 2.2, 28.5 +/- 4.4 and 18.4 +/- 2 ng/ml, respectively; p <0.05). At 1 month of age, leptin levels in breast milk were significantly lower in the LGA group than in the AGA group (15.5 +/- 4.9, 19.4 +/- 1.7 ng/ml, respectively; p<0.05). There was no difference among the three groups at 2 and 3 months of age (p>0.05). There was a positive correlation between birth Weight and breast milk leptin levels on the 15th day (r = 0.47, p = 0.001). A negative correlation was found between weight gain during the first 15 days and 1 month of life and breast milk leptin levels on the 15th day (r = -0.44, p = 0.002; r = -0.40, p = 0.005, respectively). No relationship could be determined between breast milk leptin levels and BMI of the mothers. CONCLUSION: Maternal milk of SGA, LGA and AGA infants had different leptin levels, especially during the first month of life. More rapid growth was shown in the SGA infants during the first postnatal 15 days compared to AGA and LGA infants, and human milk leptin levels were significantly reduced in the SGA group. However, LGA infants gained more weight during the second 15 days of life and breast milk leptin levels were dramatically decreased in LGA and increased in SGA infants at the end of first month of life. These findings suggest that the presence of leptin in breast milk might have a significant role in growth, appetite and regulation of nutrition in infancy, especially during the early lactation period, and the production of leptin in breast tissue by human mammary epithelial cells might be regulated physiologically according to necessity and state of the infant.     

Proportionality at birth. Associations with weight, gestational age and sex

501 small (SGA), 330 average (AGA) and 460 large for gestational age (LGA) babies were measured at birth. Head-chest, head-crown-rump length, and chest-crown-rump length ratios were used to evaluate the changing patterns of proportionality with increasing gestational age. The SGA group showed strong negative correlations for head-chest and head-length ratios, and positive correlations for chest-length ratios. The patterns were similar in the AGA group, only less evident. For all three measures of proportionality, correlations with gestational age in the LGA group were close to zero. In each group boys had higher head-chest ratios than girls.     

Proportionality at Birth

ABSTRACT. 501 small (SGA), 330 average (AGA) and 460 large for gestational age (LGA) babies were measured at birth. Head-chest, head-crown-rump length, and chest-crown-rump length ratios were used to evaluate the changing patterns of proportionality with increasing gestational age. The SGA group showed strong negative correlations for head-chest and head-length ratios, and positive correlations for chest-length ratios. The patterns were similar in the AGA group, only less evident. For all three measures of proportionality, correlations with gestational age in the LGA group were close to zero. In each group boys had higher head-chest ratios than girls.     

Birth weight categorization according to gestational age does not reflect percentage body fat in term and preterm newborns

This study was performed to prove the applicability of the small-for-gestational age (SGA), appropriate-for-gestational age (AGA), and large-for-gestational age (LGA) classification depending on birth weight to predict percentage body fat (%BF) measured by dual-energy X-ray absorptiometry (DXA) in term and preterm infants. The data of 159 healthy term and preterm neonates (87 boys and 72 girls) with a gestational age at delivery of 38.4 weeks from two longitudinal studies were analyzed. Anthropometry and body composition data were assessed within the first 10 days after birth. Correlations between anthropometric parameters and fat mass measured by DXA were calculated. Prevalences of observations with low, middle, and high %BF measured by DXA were compared between SGA, AGA, and LGA groups, according to sex and gestational age. In term infants, 42.9% of the newborns with less than 10% body fat were classified to be AGA; 9.9% of all AGA newborns had less than 10% body fat. For the whole group, among the ratios investigated, the weight-length ratio (r=0.82) showed the best correlation to fat mass measured by DXA. The %BF at the time of study was higher in girls (14.75%) than in boys (11.95%). In conclusion, traditional classification based on birth weight centiles does not reflect %BF in term and preterm newborns.     

早产和低出生体重及小于胎龄儿与脑性瘫痪发病的关系

目的 明确早产、低出生体重及小于胎龄儿(SGA)与脑性瘫痪(简称脑瘫)的关联程度。方法 1997年5—7月对江苏省7个市的1～6岁儿童进行了现况普查,共查305263名,并对其胎龄、出生体重及胎龄别出生体重与脑瘫的关系进行了分析。结果 本组儿童共发现脑瘫484例,发生率为1．59‰。早产儿及过期产儿脑瘫发生率相对危险性(RR)分别为足月儿的25．16倍及2．40倍;低出生体重及巨大儿的脑瘫发生率RR分别为正常出生体重儿的19．63倍及1．34倍;SGA及大于胎龄儿(LGA)脑瘫发生率RR为适于胎龄儿(AGA)的4．34倍及0．84倍。先按胎龄别出生体重分层再按胎龄分组,发现各层内早产儿脑瘫发生率均较足月儿高,RR最高AGA层为28．34倍,其次LGA层为21．41倍,最低SGA层为9．29倍,各层内过期产儿脑瘫发生率也较足月儿高,RR最高AGA层为2．63倍,其次SGA层为1．90倍,最低LGA层为1．55倍;先按胎龄分层再按胎龄别出生体重分组发现各层内SGA脑瘫发生率均较AGA高,RR最高足月儿层为4．41倍,其次过期产儿层为3．19倍,最低早产儿层为1．45倍,各层内LGA脑瘫发生率均不比AGA高,除足月儿层相近为0．98倍外,早产儿及过期产儿层均较AGA低,RR分别为0．74倍和0．58倍。按胎龄大小及胎龄别出生体重大小联合分成9组进行比较,发现多数组脑瘫发生率均较足月AGA组高,RR按次序为早产SGA40．99倍、早产AGA28．34倍、早产LGA21．08倍、过期SGA8．39倍、足月SGA4．41倍、过期AGA2．63倍、过期LGA1．53倍、足月LGA0．98倍;前6组差异均有显著性,后2组倍数接近1．0,差异无显著性。结论 早产及SGA两种因素均与小儿脑瘫发生率增加关联,这两个因素分别为小儿脑瘫独立的危险因素;过期产与脑瘫的关联很弱,LGA则与脑瘫的发生率增加无关。     

CONCENTRATIONS OF TRIGLYCERIDES, FREE FATTY ACIDS AND GLYCEROL IN CORD BLOOD OF NEWBORN INFANTS WITH A BIRTH WEIGHT OF ≤2700 GRAMS

Abstract Concentrations of triglycerides, free fatty acids (FFA) and glycerol were measured in umbilical venous blood from 99 infants with a birth weight of between 1100–2700 g and a gestational age of 27–41 weeks. Thirty infants were small for gestational age (SGA), 58 were appropriate (AGA) and 11 were of uncertain gestational age. In AGA infants with a gestational age of ≥35 weeks, FFA values were lower than in those with a gestational age of>35 weeks; otherwise concentrations of triglycerides, FFA and glycerol were independent of birth weight and gestational age in AGA infants. In SGA infants, higher FFA values were found compared with both AGA and term infants of normal birth weight. Triglyceride values were higher in SGA than in AGA infants. In SGA infants, a significant positive correlation was found between gestational age and concentrations of both FFA and triglycerides. No differences in FFA, glycerol and triglyceride concentrations were seen between asphyxiated and non-asphyxiated AGA infants.     

Cerebral structure and metabolism and long-term outcome in small-for-gestational-age preterm neonates

In the present study, we compared brain development and metabolism of small-for-gestational-age (SGA) and appropriate-for-gestational-age (AGA) infants using proton magnetic resonance spectroscopy ((1)H-MRS). We tested the hypothesis that intrauterine growth retardation caused by placental insufficiency is associated with changes in cerebral metabolism and is followed by an adverse neurodevelopmental outcome at the age of 2 y. Twenty-six AGA and 14 SGA (birth weight

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Metabolic and energy balance in small- and appropriate-for-gestational-age, very low-birth-weight infants

This study compared nutrient utilization and postnatal weight gain composition in eight appropriate for gestational age (AGA: birth weight 1293 ± 107 g; gestational age 28.8 ± 1.4 weeks) and eight symmetrically growth-retarded (SGA: birth weight 1110 ± 230 g; gestational age 32.7 ± 1.9 weeks), very low-birth-weight (VLBW) infants. There was no significant difference in protein, mineral and energy intake between AGA and SGA infants. Nitrogen absorption (84 ± 3 and 83 ± 4%) and nitrogen retention (356 ± 48 and 352 ± 43 mg/kg/day) were similar in both groups. Fat absorption tended to be lower in AGA (78 ± 15%) than in SGA (87 ± 4%) infants. Calcium, phosphorus and magnesium absorptions were similar in AGA and SGA infants. Metabolizable energy utilization was similar in both groups; about 55% was expended and 45% stored in new tissues. Energy expenditure was 58 ± 4 kcal/kg/day in SGA infants and 61 ± 9 kcal/kg/day in AGA infants. Weight gain and its composition were similar in both groups. We conclude that nutrient and energy utilization are similar in AGA and symmetrically growth-retarded, VLBW infants.     

The relationship between birth weight, oxidative stress and bone mineral status in newborn infants

BACKGROUND: It was shown that oxygen-derived free radicals, and particularly the superoxide anion, are intermediaries in the formation and activation of osteoclasts. Many antioxidant defence systems depend on micronutrients or are micronutrients themselves. Oxidative stress might be related to bone indices in newborn infants. AIM: To assess the relationship between oxidative status and bone indices in small-for-gestational-age (SGA), large-for-gestational-age (LGA) and appropriate-for-gestational-age (AGA) babies born to healthy mothers. METHODS: Umbilical cord venous blood samples were obtained at the delivery from 100 term newborn infants to measure plasma malondialdhyde, superoxide dismutase (SOD) and myeloperoxidase concentrations. Forty of the newborn infants had birth weights AGA, 30 were SGA and 30 LGA. Data were acquired using the whole body dual-energy X-ray absorptiometry scanner in the first 24 h after birth. RESULTS: Plasma malondialdhyde and SOD concentrations of the mothers and their newborn infants were positively correlated; however, plasma myeloperoxidase concentrations were not. SOD concentrations of SGA infants were significantly higher than those of AGA and LGA infants. Whole body bone mineral density and content were lower in SGA but higher in LGA babies than in AGA babies. Oxidative stress status of both infants and their mothers was not related to the bone indices. CONCLUSION: Our study does not provide support for the hypothesis that oxidative status of the infants and mothers may play a major role in the regulation of bone metabolism in the developing skeleton.     

Growth and catch-up growth of Australian infants of low birthweight

The growth of 90 infants of low birthweight (1500-2499 g) has been studied longitudinally from birth to 2 years of age. Seventy-five per cent of those infants were of birthweight that was appropriate-for-gestational age (AGA) and of mean gestational age 33.6 weeks (boys) and 34.5 weeks (girls). Twenty-four per cent were small-for-gestational age (SGA) and of mean gestational age 39.4 weeks (boys) and 38.5 weeks (girls). The data showed that, when gestational age was considered, the growth of AGA infants was similar to that of full-term infants of normal birthweight; SGA infants displayed accelerated growth ('catch-up'), particularly in the first months of life with upward percentile crossing from below the 5th toward the 50th. These results provide further evidence of the need to consider gestational age and whether AGA or SGA when assessing the growth of low birthweight infants.     

成都市9~15岁儿童出生情况与体格指标流行病学调查

目的：宫内环境可能对儿童生长发育产生影响,通过流行病学调查研究四川省成都市9~15岁儿童出生胎龄、体重与体格发育指标的关系。方法：调查9~15岁的中小学学生共7194名,根据出生胎龄及体重对儿童进行分类（包括小于胎龄儿、适于胎龄儿、大于胎龄儿）,测量身高、体重,并对其家长进行问卷调查。结果：被调查人群小于胎龄儿发生率为6.23%（448例）,其中身高未出现“追赶生长”（低于均值两个标准差）为5.13%,且多个年龄段儿童平均身高低于适于胎龄儿（P<0.05）。大于胎龄儿发生率为18.06% (1299例),大于胎龄儿中超重发生率为13.78% (179 例),肥胖发生率为4.39%（57例）,且多个年龄段儿童平均体重大于适于胎龄儿（P<0.05）。结论：出生时为小于胎龄儿、大于胎龄儿的儿童在远期生长发育中,可以出现身高和体重异于正常儿童,应关注这类孩子在学龄期的身高体重发育情况。     

Growth in extremely low birth weight infants up to three years

OBJECTIVE: To evaluate postnatal growth of extremely low birth weight infants (ELBW, <1,000 g) until 36 months of corrected age (CA), and to relate growth outcome to anthropometric parameters at birth, sex, fetal growth status (small or appropriate for gestational age--SGA/AGA), period of admission and major perinatal events. STUDY DESIGN/METHOD: Weight (Wt), height (Ht) and head circumference (HC) were assessed in 159 ELBW infants. Data were standardized with Z-scores following Usher and McLean and Sempe growth curves. Uni- and multivariate statistical analysis were performed. RESULTS: The mean birth weight was 851.2+/-116.5 g. Z-scores decreased from birth to term, at a deeper rate for AGA than for SGA infants (p<0.005 for Ht, Wt, and HC). Between term and 36 months, growth was better in SGA compared with AGA infants (p=0.003 for Ht). Multivariate analysis showed that anthropometric parameters at birth were positive determinants for Wt, Ht and HC at term, and also for Wt and Ht at 36 months CA (Z-scores). Oxygen therapy after 36 weeks of post-conceptional age was a negative determinant influencing growth at 36 months CA (Z-scores). CONCLUSIONS: Significant catch-up growth took place between birth and 36 months, which was greater for SGA than for AGA infants. Anthropometric parameters at birth and oxygen therapy at 36 weeks post-conceptional age are the main predictive factors for growth at 36 months CA.     

Catch up growth and pancreatic function in growth retarded neonates.

To test the hypothesis that relative pancreatic dysfunction is a determinant of catch up growth in small for gestational age (SGA) babies, 47 such babies (median gestation 38 weeks; range 27-41) and 41 appropriate for gestational age (AGA) babies matched for sex, race, and gestational age were recruited. Anthropometry was performed within 48 hours of birth and at 6 months. Faecal chymotrypsin activities were measured at 0-2 days, 14 days, 6 weeks and 6 months. At 6 months 30 SGA infants and 25 AGA infants were remeasured. In each group, median stool chymotrypsin activities doubled between 0-2 days and 6 months (9.0-25.5 IU/g SGA group; 11.6-25.3 IU/g AGA group). SGA babies had significantly lower chymotrypsin activities at 14 days (10.9 U/g) than AGA babies (15.5 U/g). In the SGA group faecal chymotrypsin activities at 0-2 days were strongly correlated with both catch up weight and with catch up length when corrected for the effects of birthweight. These data show that impaired pancreatic exocrine function at birth is associated with severe intrauterine malnutrition and with impaired catch up growth during the first 6 months of life.     

Growth and catch-up growth of Australian infants of low birthweight

Abstract The growth of 90 infants of low birthweight (1500–2499 g) has been studied longitudinally from birth to 2 years of age. Seventy-five per cent of those infants were of birthweight that was appropriate-for-gestational age (AGA) and of mean gestational age 33.6 weeks (boys) and 34.5 weeks (girls). Twenty-four per cent were small-for-gestational age (SGA) and of mean gestational age 39.4 weeks (boys) and 38.5 weeks (girls). The data showed that, when gestational age was considered, the growth of AGA infants was similar to that of full-term infants of normal birthweight; SGA infants displayed accelerated growth ('catch-up'), particularly in the first months of life with upward percentile crossing from below the 5th toward the 50th. These results provide further evidence of the need to consider gestational age and whether AGA or SGA when assessing the growth of low birthweight infants.     

Differential effects of intrauterine and postnatal brain growth failure in infants of very low birth weight

We investigated the contribution of brain growth failure to outcome in infants of very low birth weight (VLBW; less than 1.5 kg) who were appropriate for gestational age (AGA; n = 379) or small for gestational age (SGA; n = 102). Growth was assessed at birth, term, and 8 and 20 months' corrected age and results of a Bayley Mental Developmental Index (MDI) and neurologic examination were evaluated at 20 months of age. Both groups had similar 20-month MDI scores (93 vs 90) and similar rates of neurologic impairment (14% vs 10%). More SGA infants (25%) than AGA infants (14%) had a subnormal head circumference at 8 months' corrected age, indicating failure to catch up in head growth. Subnormal head size at 8 months predicted the 20-month MDI score for both groups. However, multivariate analysis indicated that, whereas subnormal 8-month head size was directly associated with the MDI score in AGA children, in SGA children 8-month head size was not significantly related to the MDI score when neonatal illness, neurologic impairment, socioeconomic status, and race were controlled for. We conclude that in AGA VLBW infants, subnormal head size at 8 months results from major neonatal illness and has adverse later effects. In SGA infants, subnormal head size at 8 months has many causes, including growth retardation in utero, which may not have an adverse effect on outcome; if subnormal head size is superimposed with neonatal illness, a poorer outcome is likely.     

Vascular retinal abnormalities in neonates of mothers who smoked during pregnancy

OBJECTIVE: To investigate whether maternal smoking during pregnancy causes retinal abnormalities in the newborn. STUDY DESIGN: One hundred sixty-two neonates of smoking mothers and 162 matched neonates of nonsmoking mothers (112 appropriate for gestational age [AGA], 30 small for gestational age [SGA], 20 large for gestational age [LGA] in each group) were studied. RESULTS: Retinal arterial narrowing and straightening (RANS) was observed in 52 and 10 eyes of the newborns of smoking and nonsmoking mothers, respectively (P <. 000001) in association with elevated blood pressure in the neonates. The frequency of RANS was more than 3-fold greater in the SGA neonates than in the AGA and LGA neonates of the smoking mothers. Retinal venous dilatation and tortuosity (RVDT) was found in 100 and 36 eyes of neonates of smoking and nonsmoking mothers, respectively (P <.000001). The frequency of RVDT in the SGA neonates of the smoking mothers was 2.5-fold and 4.2-fold greater than in the AGA infants and the LGA infants, respectively. Also, intraretinal hemorrhages were found in 61 and 31 eyes of neonates of smoking and nonsmoking mothers, respectively (P =.0007) in association with elevated hematocrit and RVDT, whereas no intraretinal hemorrhages were found when RANS was present. All retinal abnormalities resolved by 6 months in infants of smoking mothers and by 2 months in infants of nonsmoking mothers. CONCLUSIONS: Maternal smoking during pregnancy causes increased frequency of RANS, RVDT, and intraretinal hemorrhages; but these retinal abnormalities resolve by 6 months of age.     

Placental size of small-for-gestational-age infants at term

Placental size was compared between appropriate-for-gestational age (AGA) and small-for-gestational age (SGA) infants born at term. Placental weight, chorionic plate area and villous surface area were significantly reduced in the SGA infants. Although the ratio of placental weight to birth weight was similar in the AGA and SGA infants, the latter had significantly underweight placentas for their head circumference and crown-heel length. The ratios of placental weight to assessed brain weight and villous surface area to assessed brain weight were also significantly reduced in the SGA infants. It is concluded that the study SGA infants had both absolutely and relatively small placentas.     

The premature small-for-gestational-age infant during the first year of life: comparison by birth weight and gestational age

To determine the effect of intrauterine growth retardation on the outcome of the premature infant, we compared a group of 35 premature, small-for-gestational-age (SGA) infants with two groups of premature, appropriate-for-gestational-age (AGA) infants: one with similar birth weight (AGA-BW group) and the other with similar gestational age (AGA-GA group). Groups were matched by year of birth, race, gender, and socioeconomic status. Infants were free of major congenital anomalies and intrauterine infection. They were evaluated at term, at 20 and 40 weeks, and at 1 year corrected age. The SGA infants had a lower mean developmental quotient than the two groups of AGA infants. The SGA infants had significantly smaller body dimensions at birth, more nursery complications, and a higher incidence of major neurologic problems than their AGA-GA matches but were comparable to the AGA-BW matches. Poor growth constitutes an additional risk factor to prematurity. The results highlight the importance of comparing premature SGA infants with premature AGA infants of similar gestational age rather than similar birth weight.     

Effects of gestation and birth weight on the growth and development of very low birthweight small for gestational age infants: a matched group comparison

AIMS: To investigate the effects of small for gestational age (SGA) in very low birthweight (VLBW) infants on growth and development until the fifth year of life. METHODS: VLBW (< 1500 g) infants, selected from a prospective study, were classified as SGA (n = 115) on the basis of birth weight below the 10th percentile for gestational age and were compared with two groups of appropriate for gestational age (AGA) infants matched according to birth weight (AGA-BW; n = 115) or gestation at birth (AGA-GA; n = 115). Prenatal, perinatal, and postnatal risk factors were recorded, and duration and intensity of treatment were computed from daily assessments. Body weight, length, and head circumference were measured at birth, five and 20 months (corrected for prematurity), and at 56 months. General development was assessed at five and 20 months with the Griffiths scale of babies abilities, and cognitive development at 56 months with the Columbia mental maturity scales, a vocabulary (AWST) and language comprehension test (LSVTA). RESULTS: Significant group differences were found in complications (pregnancy, birth, and neonatal), parity, and multiple birth rate. The AGA-GA group showed most satisfactory growth up to 56 months, with both the AGA-BW and SGA groups lagging behind. The AGA-GA group also scored significantly more highly on all developmental and cognitive tests than the other groups. Developmental test results were similar for the SGA and AGA-BW groups at five and 20 months, but AGA-BW infants (lowest gestation) had lower scores on performance intelligence quotient and language comprehension at 56 months than the SGA group. When prenatal and neonatal complications, parity, and multiple birth were accounted for, group differences in growth remained, but differences in cognitive outcome disappeared after five months. CONCLUSIONS: Being underweight and with a short gestation (SGA and VLBW) leads to poor weight gain and head growth in infancy but does not result in poorer growth than in infants of the same birth weight but shorter gestation (AGA-BW) in the long term. SGA is related to early developmental delay and later language problems; however, neonatal complications may have a larger detrimental effect on long term cognitive development of VLBW infants than whether they are born SGA or AGA.