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.     

Influence of gestational age and intrauterine growth on leptin concentrations in venous cord blood of human newborns

BACKGROUND: The ob gene product leptin is involved in the regulation of body weight and energy expenditure, suggesting a potential role of leptin in embryonal and fetal development and progression of pregnancy. In term infants, leptin concentrations showed a positive correlation with birth weight. We aimed at comparing leptin cord blood levels in AGA (appropriate for gestational age) to SGA (small for gestational age) preterm and term newborns. PATIENTS AND METHODS: Ninety-seven human newborns, 47 females and 50 males, 33 born at term and 64 born before 36 weeks of gestation, were studied prospectively. Leptin concentrations in venous cord blood were determined using a specific RIA (radioimmunoassay). RESULTS: In term newborns, mean gestational age (GA) was 39 weeks (wk) (+/- 0.7 wk) and mean birth weight (BW) was 3316 g (+/- 473 g); in preterm newborns (n = 64), mean GA was 30 wk (+/- 5.0 wk) and mean BW was 1398 g (+/- 505 g). Mean standard deviation score of birth weight (BW SDS) was calculated as - 0.47. Mean leptin concentrations in term newborns differed significantly from those in preterm newborns (9.21 +/- 2.63 ng/ml vs. 1.58 +/- 0.88 ng/ml; p < 0.0001). In preterm and term infants, leptin concentrations showed a linear correlation with BW (r = 0.46; p < 0.0001) and GA (r = 0.48; p < 0.0001), respectively. Leptin levels were best predicted by an exponential regression model with GA (Leptin = exp(- 4.41 + 0.14 x GA); r = 0.61; p < 0.0001). Using multivariate regression analysis (r = 0.57; p < 0.0001), we found significant influences of GA (p < 0.00001) and BW SDS (p < 0.05) on leptin levels. No difference was observed between leptin values in AGA versus SGA preterm infants. CONCLUSION: These data suggest fetal leptin levels to be primarily determined by GA and additionally modulated by growth restriction in term newborns. We found a dramatic increase at weeks 33 to 35 of gestation and no modulation by BW SDS in very preterm infants.     

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.     

Placental findings in malnourished term neonates

Background:  The aim of the present study was to investigate placental pathologies in malnourished term neonates.
Methods:  A group of term newborns was evaluated at birth for fetal malnutrition (FM) using the Clinical Assessment of Nutritional Status (CANS) score. The study group consisted of 37 malnourished neonates and 13 well-nourished newborns, including their placentas. Infants with FM were subdivided into two groups: appropriate for gestational age (AGA) and small for gestational age (SGA).
Results:  The proportion of subjects having antepartum complications was 18.9% in the FM group, whereas none was found in the control group. Similarly, a significant portion, 83.8% of the study group, had gross placental abnormalities, while the control group had none. The placental microscopic findings in the study group included perivillous fibrin deposition, calcification, necrosis, retroplacental hematoma, and infarction. In contrast, the control group had only perivillous fibrin deposition and calcification. Placental histopathological findings between FM term AGA and SGA neonates were also compared, and no statistically significant differences were found ( P  < 0.05).
Conclusions:  Placental findings in malnourished term AGA neonates are not different from findings documented in malnourished SGA cases, but they are different from those in well-nourished term AGA newborns.     

Exercise performance in very low birth weight children at the age of 7–12 years

Fifteen very low birth weight children, 9 appropriate for gestational age (AGA, mean birth weight 1302 ± 164 g) and 6 small for gestational age children (SGA, mean birth weight 1263±117 g), were studied at the age of 7–12 years, and compared to a group of 26 healthy, age-, sex-, and height-matched children born at term. None of the VLBW children had developed chronic bronchopulmonary disease. Pulmonary function tests and progressive exercise tests on a treadmill were performed. Forced vital capacity, forced expiratory volume at 1 s and forced expiratory flow between 25% and 75% of vital capacity were normal for all subjects. No differences were found in maximum oxygen consumption, anaerobic threshold and maximal heart rate between the AGA and SGA children and the respective controls. Both in the AGA and SGA subgroups, the pre-exercise oxygen uptake results were comparable to those of the controls. In the SGA subgroup the energy cost of running was significantly higher with respect to the controls, while no difference was found between the AGA and the control children. In conclusion, children with birth weight less than 1501 g have normal values of aerobic fitness. In SGA children the efficiency of running is slightly reduced.     

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。     

The Association between Weight for Gestational Age and Kidney Volume: A Study in Newborns in India

Objective: The association of low birth weight (LBW) with adult onset diseases like hypertension is suggested to be partially mediated by a low number of nephrons at birth. Studies have established a relation between LBW and renal volume as the latter is a surrogate marker of total nephron number. Most such studies have considered birth weight or gestational age as separate independent predictors, without taking into consideration the baby’s weight with respect to its gestational age. This study aims to investigate the influence of weight for gestational age on kidney volume in newborns. Methods: Consecutive newborns delivered in the department of neonatology in a tertiary care medical college and hospital, were included in a cross-sectional study. The subjects were classified as appropriate for gestational age (AGA) and small for gestational age (SGA) as per Lubchenco’s charts of weight for gestational age (WGA). Bilateral kidney dimensions were measured by a single observer and combined kidney volumes were calculated and compared between the groups. Findings : Four hundred and seventeen newborns (SGA 159; AGA 258) were included. The mean combined kidney volume (CKV) was significantly lower among SGA newborns (13.85±4.02 cm³) compared to that of AGA (16.88±4.53 cm³) (P<.001). Univariable and multivariable analyses were done for assessing the effect of demographic, anthropometric and maternal parameters on CKV. WGA, crown heel length, gestational age and postnatal age (hours of life) were independent predictors of mean CKV. An SGA newborn was expected to have a mean CKV 1.57 cm less (95% CI -2.49 cm to -0.65 cm) than that of its AGA counterpart. Conclusion: Considering the future implications of being SGA and having low kidney volumes at birth, it is essential to have an objective depiction of the relationship between these two vital parameters. This study from the Indian subcontinent brings forth such an association.Key Words: Small for Gestational Age, Newborn, Kidney, Low Birth Weight     

34 周以下适于胎龄及小于胎龄早产儿出生 2 周内 蛋白质、能量摄入及体质量变化

目的了解34周以下早产适于胎龄儿(AGA)和小于胎龄儿(SGA)生后蛋白质、能量摄入量以及体质量z评分的变化情况。方法回顾收集2012年1月至2014年12月入院的314例早产儿,比较268例AGA和46例SGA早产儿生后2周内蛋白质、能量摄入情况和体质量变化。结果 SGA组住院时间、肠外联合肠内营养时间、全肠内营养时间、达足量喂养时间均较AGA早产儿长,差异有统计学意义(P??0.05);SGA组生后第4、8、12天能量摄入量明显低于AGA组,SGA组生后第6、8天总蛋白质摄入量明显低于AGA组,差异均有统计学意义(P??0.05);SGA组日平均体质量增长量大于AGA组,差异有统计学意义(P??0.05);AGA组与SGA组生后2周内体质量z评分均逐渐远离中位水平,且SGA组2周时体质量z评分低于AGA组(P??0.05)。结论胎龄??34周的SGA早产儿恢复出生体质量后的生长速率快于AGA早产儿,存在一定的追赶生长;但SGA、AGA早产儿的生长均有待提高。     

小于胎龄儿新生儿期ghrelin水平与生长轴关系的研究

目的通过比较小于胎龄儿（SGA）与适于胎龄儿（AGA）新生儿早期血ghrelin水平和代谢促生长轴各因素的差别和相关性,探索ghrelin在SGA发病机制中的作用。方法通过配对对17例SGA和17例AGA的血清ghrelin、IGF-1、生长激素、胰岛素、血糖浓度进行比较并分析其差异的意义。结果与AGA组相比,SGA组血ghrelin水平显著升高（P〈0．05）,血IGF-1、胰岛素水平显著下降（P〈0．05）,血生长激素和血糖水平差异无统计学意义。结论与AGA相比,SGA新生儿有高ghrelin血症。SGA新生儿的高血ghrenlin水平伴随其低下的出生体重、身长、血IGF-1、胰岛素水平,在一定程度上反映了其宫内营养不良状况。ghrelin作为胰岛素的反调节激素,SGA的ghrelin高分泌可能是宫内能量负平衡所致低胰岛素、低IGF-1状态反馈和／或重整性调控的结果。     

A study of serum zinc levels in cord blood of neonates and their mothers

Serum zinc was estimated in the cord blood of 60 neonates of different gestational age and birth weight, and their mothers. Mean serum zinc levels in neonates FTGA, PTAGA and term SGA were 128.88±14.37, 94.32±17.79 and 111.8±9.2 ug/dl respectively. The maternal serum zinc levels in corresponding groups was 96.28±19.48, 115.44±15.41 and 93.8±7.62 ug/dl. Thus mean serum zinc level in cord blood of FT AGA newborns was significantly higher than that in PT AGA and FT SGA. Mean serum zinc level in mothers of FT AGA was significantly lower than that in mothers of PT AGA. However, there was no significant difference between the maternal serum zinc levels of FT AGA and FT SGAs. There was positive correlation between gestational age and serum zinc level in cord blood of AGAs while correlation was negative in case of their mothers. There was positive correlation between weight (keeping gestational age constant) and serum zinc level in case of neonates while corresponding maternal zinc levels did not vary. (FT AGA and FT SGA).     

Total energy expenditure in small for gestational age infants.

OBJECTIVE: To measure total energy expenditure and body composition in small for gestational age (SGA) infants, to investigate hypermetabolism. METHODS: A cross-sectional study was performed in 52 small for gestational age (SGA) measured at 5 weeks of age, using existing data from appropriate for gestational age (AGA) infants as controls. The doubly-labelled water technique was used to assess both total energy expenditure and body composition in both cohorts of infants. RESULTS: Multiple regression analysis revealed that expressing energy expenditure per kg fat free mass adjusts for body composition in infants of this age. Regression analysis also showed that the relation between total energy expenditure and fat free mass differed between the two groups. CONCLUSION: These data indicate that for a given fat free mass, the total energy expenditure of SGA infants is greater than that of AGA infants. Such data should be taken into account when energy requirements for SGA infants are being considered.     

Growth of premature infants fed own mother's milk supplied with two milk formulas

The purpose of the authors in this article was to evaluate the effects of supplementing maternal milk with two different caloric formulas on the growth of premature newborns until they reached 40 weeks of post-conceptional age. Seventy premature infants weighing < 1750g at birth were randomized: 35 adequate for gestational age (AGA) and 35 small for gestational age received maternal milk and either a special preterm formula or a modified formula. Anthropometric measurements and clinical evaluations were used to determine the nutritional status and the postnatal growth of these infants, who were analyzed in six different moments: at maximum weight loss, at return to birth weight, at definite weight gain, when exclusively fed with formula, at 2000g, and when they reached 40 weeks of post-conceptional age. The AGA premature newborns on preterm formula had greater daily weight gain, cephalic circumference increase and growth. The SGA premature newborns on preterm formula had greater daily weight gain and cephalic circumference increase observed from the third week of life onward. The AGA premature newborns on modified formula had less weight gain and smaller increments in the cephalic circumference. The SGA premature on modified formula had the worst anthropometric results. The preterm formula was more efficient than the modified formula in promoting postnatal growth of AGA and SGA premature infants. We believe that, due to their special characteristics, SGA premature should receive individualized nutritional caloric planning     

Total energy expenditure in small for gestational age infants.

AIM: To measure total energy expenditure and body composition in small for gestational age (SGA) infants in order to investigate proposed hypermetabolism in such babies. METHODS: A cross sectional study of 52 SGA infants measured at 5 weeks of age was made, using existing data from appropriate for gestational age (AGA) infants as controls. The double labelled water technique was used to assess both total energy expenditure and body composition. RESULTS: Multiple regression analysis showed that expressing energy expenditure per kg fat free mass adjusts for body composition in infants of this age. The relation between total energy expenditure and fat free mass differed between the two groups. CONCLUSION: These data indicate that for a given fat free mass the total energy expenditure of SGA infants is greater than that of AGA infants. Such data should be taken into account when energy requirements for SGA infants are being considered.     

Effects of prematurity and dysmaturity on growth at age 5 years

Forty-two term and 106 preterm appropriate for gestational age (AGA), and 43 term and 31 preterm small for gestational age (SGA) children were observed from birth to age 5 years. Parents' weight and height were also measured in 193 subjects including 97 couples. The percentage of short children was higher in SGA (17%) than in AGA (3.4%) children (P less than 0.01). This difference was significant in the preterm but not in the term children, suggesting that early failure of growth in utero can result in reduced growth in children. The findings were similar for weight and head circumference, but microcephaly was more frequent in term SGA (30%) than in preterm SGA (6.4%) children (P less than 0.05), suggesting that late impaired growth in utero can result in poor growth of the head. Height at the age of 5 years correlated with the parents' height only in AGA children, and with length at birth in SGA children. Weight of the 5-year-old children correlated with the mother's weight only in AGA children. Multivariate analysis in 66 couples and their children confirmed a greater tendency toward the influence of parental factors in AGA children and a more significant relationship with perinatal factors in SGA children.     

Effects of prematurity, intrauterine growth status, and early dexamethasone treatment on postnatal bone mineralisation

AIM: To examine the hypothesis that, apart from prematurity, intrauterine growth status (expressed as gestational age specific birth weight standard deviation scores), neonatal factors, and duration of dexamethasone treatment influence bone mineralisation in early infancy. METHODS: In this prospective study, groups consisted of 15 preterm small for gestational age infants (SGA group) and 43 preterm appropriate for gestational age infants (AGA group). A reference group contained 17 term infants. Body size is known to affect bone mineral content (BMC), therefore postnatal bone mineralisation was measured when the study infants and controls had attained a similar body size. Bone mineral density (BMD) and BMC were determined by dual energy x ray absorptiometer of the lumbar spine (L2-L4). RESULTS: Both preterm groups had significantly lower BMC and BMD than the weight matched term reference group, but no difference was found in BMC and BMD between preterm SGA and AGA infants. In stepwise regression analysis, bone area, duration of dexamethasone treatment, weight at examination, and weight gain per week were the most significant factors, explaining 54% of the variance of the BMC values. CONCLUSION: In particular, weight at examination, prematurity, and possibly dexamethasone treatment, but not intrauterine growth status, affect postnatal bone mineralisation.     

Term infants with fetal growth restriction are not at increased risk for low intelligence scores at age 17 years

OBJECTIVE: To assess the long-term cognitive outcome of small for gestational age (SGA) compared with appropriate for gestational age (AGA) infants. DESIGN: Data from the Jerusalem Perinatal Study was matched with information from the army draft medical board. SGA and severe SGA were defined as birth weight below the 10th and 3rd percentiles for gestational age, respectively. A multiple linear regression analysis was performed to control for clinical, perinatal, and socio-demographic confounding variables. SUBJECTS: A cohort of 13,454 consecutive singleton term infants born between 1974 and 1976. Main outcome measure: IQ at age 17 years. RESULTS: SGA infants had lower adjusted mean +/- SE IQ scores compared with their AGA peers: 102.2 +/- 0.9 versus 105.1 +/- 0.7 (P <.0001) for males and 102.5 +/- 0.9 versus 103.9 +/- 0.7 (P <.015) for females. SGA was not associated with lower academic achievements compared with AGA. CONCLUSION: After controlling for multiple confounders, being born SGA at term is associated with slightly lower intelligence test scores at age 17 years. However, the clinical significance of the small difference is not evident in academic achievements.     

Association between serum leptin and anthropometric parameters at birth and at 15th day of life in infants born asymmetrically small for gestational age

The aim of this study was to investigate changes in skinfold measurements taken at three sites, mid-arm circumference and umbilical circumference during the first 15 days of life; and to evaluate relationships between anthropometric measurements and umbilical cord blood serum leptin levels in infants born small for gestational age (SGA) and appropriate for gestational age (AGA) infants. Of 50 newborn infants, 25 were SGA and 25 were AGA. Neonates' weight, mid-arm circumference (MAC), umbilical circumference (UC), and triceps, subscapular and periumbilical skinfold thicknesses were measured (Holtain callipers) immediately after delivery. Anthropometric parameters were measured again at 15th days of age. At birth, mean birth weight, mean skinfold thickness, MAC and UC measurements in the AGA group were significantly higher than those of the SGA group. These differences were also found on the 15th day. Birth weight correlated with all skinfold thicknesses, MAC and UC at birth. Weight at 15th day of life correlated with skinfold thicknesses, MAC and UC at 15th day of life. Cord blood leptin level was significantly lower in the SGA than in the AGA infants. This difference continued on the 15th day. When cord blood leptin level was compared with that of the 15th day, we found that leptin levels in the cord blood were significantly higher. There were significantly positive correlations between leptin levels and birth weight and skinfold thicknesses when the infants were all grouped together. When the newborns were grouped according to birth weight, there were positive correlations between cord blood serum leptin levels and these parameters in the AGA group, but no correlation in the SGA group. At the 15th day of life serum leptin levels correlated with weight, subscapular and triceps skinfold thickness in the AGA group, but only with triceps skinfold thickness in the SGA group.     

Optimal birth weight percentile cut‐offs in defining small‐ or large‐for‐gestational‐age

Aims: It remains questionable what birth weight for gestational age percentile cut‐offs should be used in defining clinically important poor or excessive foetal growth. We aimed to evaluate the optimal birth weight percentile cut‐offs for defining small‐ or large‐for‐gestational‐age (SGA or LGA). Methods: In a birth cohort‐based analysis of 17 979 120 non‐malformation singleton live births, U.S. 1995–2001, we assessed the optimal birth weight percentile cut‐offs for defining SGA and LGA. The 25th–75th percentile group served as the reference. Primary outcomes are the risk ratios (RR) of neonatal death and low 5‐min Apgar score (<4) comparing SGA or LGA versus the reference group. More than 2‐fold risk elevations were considered clinically significant. Results: The 15th birth weight cut‐off already identified SGA infants at more than 2‐fold risk of neonatal death at pre‐term, term or post‐term, except for extremely pre‐term births <28 weeks (continuous risk reductions over increasing birth weight percentiles). LGA was associated with a reduced risk of low 5‐min Apgar score at pre‐term, but an elevated risk at term and post‐term. The 97th cut‐off identified LGA infants at 2‐fold risk of low 5‐min Apgar at term. Conclusion: The commonly used 10th and 90th birth weight percentile cut‐offs for defining SGA and LGA respectively seem largely arbitrary. The 15th and 97th percentiles may be the optimal cut‐offs to define SGA and LGA respectively.     

Children born small for gestational age are not at special risk for preschool emotion and behaviour problems

Despite the wealth of literature examining long term outcomes of preterm low birthweight children, few studies have directly assessed the developmental impact of being born full term but small for gestational age (SGA). We aim to determine whether (i) being SGA increases preschool behavioural problems and (ii) other risk factors operate differently in SGA and appropriate for gestational age (AGA) controls. 550 New Zealand European mothers and their 3.5 year old children participated in this study. All children were born at full term (>37 weeks' gestation) and approximately half were SGA (≤sex specific 10th percentile for gestation) the remainder were AGA controls. Extensive data were collected at the child's birth, 1 year and 3.5 years. Behavioural problems were measured when children were 3.5 years, using the Strengths and Difficulties Questionnaire (SDQ). Multiple regression analyses were used to examine the associations between risk factors and behavioural problems; statistical weighting was used for analyses of the total study group. There was no significant difference in behavioural problems between SGA and AGA groups. In the total sample the significant predictors of behavioural problems included: mothers' school leaving age; smoking during pregnancy; maternal alcohol use during pregnancy; and absence of the father. Predictors of behavioural problems were found to be the same for SGA and AGA groups. These results do not support the view that SGA is a risk for behavioural preschool difficulties or that SGA children are sensitised to risks known to be associated with such difficulties in the preschool years.     

脑源性神经营养因子与新生儿出生体重的关系

目的：该文通过检测新生儿脐血脑源性神经营养因子（brain-derived neurotrophic factor,BDNF）的水平,探讨BDNF与新生儿出生体重的关系,并对相关因素进行分析。方法：根据出生体重,将51 例足月第1胎健康新生儿分为3 组:①小于胎龄组（SGA）8例;②适于胎龄组（AGA ）31例;③大于胎龄组（LGA）12例。测量新生儿身长、体重及其母亲的身高、体重,并对脐血中BDNF、瘦素（LEP）、胰岛素（INS）、总胆固醇（TC）、甘油三酯（TG）进行检测。结果：SGA组的BDNF明显高于AGA组和大于LGA组,AGA组和LGA组中BDNF没有差异;多元逐步回归分析显示BDNF值与新生儿出生体重、体重指数存在负相关关系。LEP与BDNF不呈相关趋势（P>0.05）,INS与BDNF也不呈相关趋势（P>0.05）。INS 与LEP呈现正相关（P<0.05）。LEP与新生儿体重、产妇体重及其BMI呈正相关,而TC,TG在3组新生儿中差异无显著性。结论：BDNF是新生儿体重的重要影响因素,而且不受LEP,INS的影响。