Bone mineral content in preterm infants at age 4 to 16

Using photon absorptiometry the forearm bone mineral content (BMC) was determined in 75 children aged 4 to 16, who all had a low birth weight. Forty-five of them were born preterm AGA (27 boys, 18 girls, mean weight 1 580 g; range 920-2 060 g) and 30 preterm SGA (17 boys, 13 girls, mean weight 1510; range 940-2130 g). The results were compared with a control group of children of the same age, and analyses of covariance with age, height and weight as the covariant factors were performed. The BMC, weight and height did not differ between the children born AGA or SGA. Irrespective of AGA or SGA, the BMC was significantly decreased in boys but the difference was less pronounced and less significant when height and weight were used as covariant factors. Boys who had been born preterm had a less BMC than the control boys for their age but they were also somewhat shorter and lighter than expected with regard to their age.     

Bone Mineral Content in Preterm Infants at Age 4 to 16

Using photon absorptiometry the forearm bone mineral content (BMC) was determined in 75 children aged 4 to 16, who all had a low birth weight. Forty-five of them were born preterm AGA (27 boys, 18 girls, mean weight 1580 g; range 920-2060 g) and 30 preterm SGA (17 boys, 13 girls, mean weight 1510; range 940-2130 g). The results were compared with a control group of children of the same age, and analyses of covariance with age, height and weight as the covariant factors were performed. The BMC, weight and height did not differ between the children born AGA or SGA. Irrespective of AGA or SGA, the BMC was significantly decreased in boys but the difference was less pronounced and less significant when height and weight were used as covariant factors. Boys who had been born preterm had a less BMC than the control boys for their age but the were also somewhat shorter and lighter than expected with regard to their age.     

Pubertal development in children born small for gestational age

Reduced fetal growth appears to be associated with precocious adrenarche, early puberty and polycystic ovary syndrome with subsequent fertility problems. We investigated pubertal development and DHEAS levels in children born small for gestational age (SGA) and children born appropriate for gestational age (AGA). Physical examination was carried out twice. Mean age (+/-SD) at the first visit: SGA group, 9.1+/-1.1 yr; AGA group, 9.0+/-1.1 yr. AT FOLLOW-UP: SGA group, 11.6+/-1.0 yr; AGA group, 11.6 +/-1.1 yr. Pubertal stages of the children were assessed. Pubic hair was recorded as a measure of androgenization. Chronological age (CA) was expressed as a percentage of the age corresponding to the pubertal stage (CA/pubertal age [PA] x 100%). Estradiol, testosterone and dehydroepiandrosterone sulfate (DHEAS) were measured in all children. FIRST VISIT: All children were prepubertal without signs of pubarche. DHEAS concentrations were higher in SGA children than in AGA children (p = 0.004). FOLLOW UP: Twenty SGA children and 15 AGA children were pubertal. CA/PA x 100% was lower in SGA girls than in AGA girls (p = 0.004). Since 2.5 years earlier all girls had been prepubertal, this means a more rapid progression in the SGA girls. CA/PA x 100% was similar in SGA and AGA boys (p = 0.1). DHEAS levels tended to be higher in SGA children than in AGA children (p = 0.06). These data support that a low birth weight may have long-lasting effects on pubertal development, as observed in a more rapid progression in SGA girls. In prepubertal SGA children, an exaggerated adrenarche is observed compared to AGA children, which tended to persist through puberty.     

Language assessment of non‐handicapped twins at 5 years of age

Background: The aim of the present study was to determine language levels in twins and singletons born after at least 34 weeks gestation and without identifiable neurological abnormality and to evaluate whether in vitro fertilization (IVF) affects language development in twin pregnancies. Methods: A prospective study of a large cohort of all children born between 1 January 2001 and 31 December 2003 was carried out at Gazi University Hospital. All live‐born twin pairs in which both twins survived were identified, and a comparable sample of families with pairs of singletons were chosen. The Stanford–Binet Intelligence Scale Form and the translated Turkish form of the Peabody Picture Vocabulary Test were completed at 60 months. Results: Even after excluding the most premature twins and those with diagnosable neurological damage, twins performed worse than singletons on language development tests. Twin girls had better scores than twin boys. A statistically significant difference was found between the scores of term and preterm twins. No significant difference was noted when compared according to birth order. Appropriate for gestational age (AGA) twins did better than small for gestational age (SGA) twins in the test scores. All twin girls did not differ from singleton girls, but all twin boys performed worse than singleton boys. Term twins had similar results with term singletons, but preterm twins had lower scores than preterm singletons. SGA singletons had better scores than SGA twins, while AGA twins and singletons did not differ. When the children were compared with regard to method of conception, IVF children had significantly lower scores on the tests than those in the spontaneous conception group. Conclusion: It is hoped that the present findings could lead to a more precise assessment of children for speech impairment and, above all, to more efficient preventive intervention. Whatever mechanisms are involved, the present results indicate that twins born as a result of IVF, are at a disadvantage in terms of language development in comparison with spontaneously conceived twins.     

Normal thyroid function in young adults who were born very preterm

There is some evidence for elevated thyrotropin (TSH) levels in children born preterm, but follow-up studies into adulthood are lacking. We tested whether thyroid function in young adults born at a gestational age < 32 weeks, with either an appropriate (appropriate for gestational age, AGA) or low birth weight for gestational age (small for gestational age, SGA), differed from that in age-matched controls. We made our measurements when the study participants reached 21 years of age. Serum concentrations of TSH and free T4 (fT4) and body composition were measured in subjects born preterm and AGA (n = 29) or SGA (n = 28), and in non-preterm controls (n = 30). The TSH and fT4 concentrations of participants were within normal limits. Free T4 levels in subjects born preterm were slightly higher than those in controls: 17.0 +/- 2.4 (AGA) and 17.2 +/- 1.7 (SGA) vs. 16.1 +/- 1.9 pmo/L (p = 0.04). TSH concentrations did not differ between groups. From these preliminary data, we conclude that young adults born preterm have a normal thyroid function.     

小于胎龄儿青春前期女孩硫化脱氢表雄酮和胰岛素水平的研究

目的探讨小于胎龄儿(SGA)青春前期女孩肾上腺机能初现及是否具有肾上腺机能早现、高肾上腺雄激素血症、高胰岛素血症和胰岛素抵抗现象。方法以符合纳入标准的SGA 39例为研究对象,年龄(7.4±1.7)岁,42例适于胎龄儿(AGA)为对照组,年龄(7.4±1.7)岁。在隔夜空腹12 h后,行身体检查,并抽血检测空腹血糖、胰岛素、硫化脱氢表雄酮(DHEAS)、皮质醇和雌二醇。胰岛素敏感性用空腹血糖与胰岛素乘积的倒数再取自然对数来评价。结果两组中未发现肾上腺机能早现的临床表现,两组间孕母孕龄、年龄、体重指数、空腹血糖、皮质醇、雌二醇和胰岛素敏感性指数差异无统计学意义。SGA组出生体重、研究时的身高和体重均低于AGA组,SGA血清胰岛素和DHEAS水平均高于AGA组(对数转换值:1.076±0.041vs.1.050±0.051,P<0.05;2.637±0.271vs.2.514±0.250,P<0.05)。AGA组DHEAS值在7岁以后出现明显增加,SGA组DHEAS值出现增加的趋势与AGA组比较有所提前。结论AGA女孩肾上腺机能初现的年龄约为7岁,而SGA女孩肾上腺机能初现有始动提前的趋势,青春前期SGA女孩有高肾上腺雄激素血症和胰岛素水平升高的现象,但以胰岛素敏感性指数来评价,尚未发现胰岛素抵抗现象。     

Birthweight and stature, body mass index and fat distribution of 14-year-old Polish adolescents

OBJECTIVES: The relationships between intra-uterine growth retardation and stature, relative weight and fat distribution at adolescence have not been comprehensively established. The aim of this report is to assess the effect of low birthweight on stature, relative weight and fat distribution in 14-year-old boys and girls from Wroclaw, Poland. METHODOLOGY: Cross-sectional measurements of 1197 boys and 819 post-menarcheal girls aged 13.50-14.49 years were performed during medical examinations in 1997. Stature, body mass index (BMI; kg/m2), waist-to-hip ratio (WHR) and waist-to-thigh ratio (WTR) were used in the present study. A cut-off value of the 10th percentile of birthweight for particular gestational weeks was used in order to define subjects born small for gestational age (SGA) or appropriate for gestational age (AGA). Two-way ANOVA was used to evaluate the effect of birthweight on anthropometric variables of 14-year-old adolescents, allowing for socioeconomic status (determined by the level of the mother's education). RESULTS: Birthweight affected stature in boys and girls (P < 0.001), BMI in boys (P < 0.05) and WHR and WTR in girls (P < 0.001 and P < 0.05, respectively). At the age of 14 years, both SGA boys and girls were shorter than their AGA peers. The SGA boys had lower BMI, whereas SGA girls accumulated more centralized fat compared with their AGA counterparts. CONCLUSION: Fetal growth retardation has a long-lasting adverse effect on later physical growth. Polish SGA children do not catch up with their peers in terms of stature by adolescence. Moreover, central fat distribution, as observed among SGA girls, constitutes a significant risk for several adult degenerative diseases.     

Die neurologische und kognitive Entwicklung zu klein geborener Kinder

This article aims to provide an overview on the neurological and cognitive outcome of children who were “born too small”. We will discuss the neurodevelopmental prognosis of term born small for gestational age children, and for children born prematurely (appropriate and small for gestational age). The various underlying causes responsible for intrauterine growth retardation (IUGR) and significance for neurodevelopmental outcome will be discussed briefly. Neurodevelopmental outcome of term born children with IUGR due to intrauterine malnutrition and outcome of preterm born small for gestational age (SGA) as well as preterm born appropriate for gestational age (AGA) children will then be discussed in more detail. Children with IUGR represent a heterogeneous group regarding the underlying cause that is responsible for the growth retardation. Neurodevelopmental prognosis very much depends on the specific underlying cause. IUGR caused by intrauterine malnutrition is not necessarily associated with neurodevelopmental problems. However, results of several studies suggest that in term born children with IUGR mild neuromotor problems and lower full scale IQ is more frequent when compared with term born appropriate for gestational age children. Prematurely born children are at high risk for neurodevelopmental impairment. There is no difference in frequency of disabling impairments between AGA and SGA preterm children. However, in preterms with IUGR there seems to be a higher frequency of mild neuromotor problems and cognitive function seems to be poorer than in appropriate for gestational age preterms.     

Preterm birth and carotid diameter and stiffness in childhood

BACKGROUND AND AIM: Low birthweight, either as a result of poor foetal growth or preterm birth, is a risk factor for stroke in adult life. Carotid stiffening, an early marker of atheromatous disease, has been found in low-birthweight children born at term. We hypothesized that carotid artery growth and dynamic properties are permanently affected by preterm birth. METHODS: Carotid artery stiffness and dimensions in 56 school children, 39 born very preterm (mean gestational age [GA] 29 weeks) and 17 controls born at term, were studied by ultrasonic measurements of the pulsatile movements of the vessel wall. RESULTS: The carotid artery diameter was 6.4 mm both in children born preterm and at term (p=0.99). No difference in carotid stiffness was found. Within the preterm group, no differences could be seen between those born small for gestational age (SGA) or appropriate for gestational age (AGA). CONCLUSIONS: Carotid artery elasticity and structure are not altered after preterm birth. The mechanisms behind the increased stroke risk in adults born preterm remain unresolved.     

Peripheral nerve conduction velocity and brainstem auditory evoked responses in small for gestational age preterm infants

Ulnar nerve conduction velocity (NCV) and brainstem auditory evoked responses (BAER) were measured in each of 11 preterm small for gestational age (SGA) infants born at less than 35 weeks gestation. The mean motor NCV in the SGA infants was similar to that reported for infants who were appropriately grown for their gestational age (AGA). However, the mean central conduction time of the BAER in SGA infants was significantly shorter than that of AGA infants of the same post-menstrual age. Thus, the precocious development of auditory brainstem neural function in preterm SGA infants is not accompanied by changes in functional maturation of the peripheral motor nerves.     

Preschool children born moderately preterm have increased waist circumference at two years of age despite low body mass index

Aim: To investigate the development of waist circumference (WC) in preschool children born preterm compared with a population‐based reference. Background: Children born preterm are reported to be insulin resistant, despite being lean during early childhood. We hypothesize that the mechanism is through increased visceral adiposity. Methods: Data from 4446 preschool children (2169 girls/2277 boys) born in 2001–2006 from a population‐based study were compared with longitudinal measurements of body mass index (BMI) and WC from a cohort of 152 children (64 girls/88 boys) born moderately preterm in 2002–2004 (gestational age, 32–37 weeks). Results: In the preterm children, the mean WC was 2.8 cm larger compared with the reference group (p < 0.001) at 2 years of age but not at 5 years of age. There was no significant difference in the mean BMI at 2 years of age. The preterm group was significantly leaner at 5 years of age, with a mean BMI of 15.13 compared with 15.98 in the reference group (p < 0.001). Conclusion: Children born moderately preterm present as lean during early childhood but have an increased waist circumference in infancy, pointing towards a change in fat distribution with more abdominal fat. This may have implications for their metabolic status.     

Development of smooth pursuit eye movements in very preterm infants: 1. General aspects

Aim: To investigate early oculo‐motor development in a population‐based cohort of very preterm infants. Methods: Early oculo‐motor development was prospectively studied by measuring smooth pursuit eye movements at 2 and 4 months corrected age in a population of very preterm infants born in Uppsala County 2004–2007. Eighty‐one preterm infants were studied, and 32 healthy term infants constituted the control group. Results: The study group consisted of infants with a mean gestational age of 28 + 5 weeks. At 2 and 4 months corrected age, infants born very preterm showed lower gain (p < 0.001) and proportion of smooth pursuit eye movements (p < 0.001) compared to the control group. The boys showed higher gain of smooth pursuit eye movements at both 2 and 4 months corrected age, compared to girls. Conclusions: Oculo‐motor development measured by smooth pursuit eye movements is delayed in very preterm infants at 2 and 4 months corrected age. This might be a risk factor or early indicator of later perceptual and behavioural impairment.     

Determinants of visual evoked potentials in preterm infants

The latency and amplitude of N1, the first negative peak of single flash visual evoked cortical potentials (VEP) were evaluated in 86 preterm infants (25-34 weeks of gestation), investigated during the first day of life. All infants were regarded stable at the time of investigation and none had experienced severe asphyxia. Both the VEP latency and amplitude were inversely related to gestational age. When latency was corrected for age it was longer in boys than in girls. Age corrected VEP amplitude was inversely related to head circumference, umbilical cord pH and EEG activity. There was no difference between VEP parameters in asymmetrically growth retardated infants compared to those with normal growth. Administration of dexamethasone to the mother before delivery, mode of delivery, presence of hyaline membrane disease, mode of assisted ventilation or imminent development of periintraventricular haemorrhage did not affect the VEP.     

Whole blood fatty acid composition differs in term versus mildly preterm infants: small versus matched appropriate for gestational age

To investigate the associations between whole blood fatty acid (FA) profile and restricted intrauterine growth, any small for gestational age (SGA) infant born in our maternity ward through 1 y was matched with two appropriate for gestational age (AGA), of the same GA +/- 0.5 wk, infants, further subdivided into term and preterm. Whole blood was collected at d 4 on a strip and FA % composition assessed by means of gas chromatography. The whole sample consisted of 28 SGA versus 56 AGA born at term and 20 SGA versus 40 AGA born preterm at around 35 wks. Parent FA of the n-6 and n-3 FA families were higher in preterm groups, whereas docosahexaenoic acid was higher in term AGA (median % values, 3.9 versus 3.7 in term SGA, 2.8 in preterm AGA, and 2.5 in preterm SGA, p < 0.001). Term AGA had markedly higher values for the docosahexaenoic acid/alpha-linolenic acid ratio (median value: 91, versus 18 in term SGA, 12 in preterm AGA, and 10 in preterm SGA, p < 0.001). Term SGA had significantly lower levels of total monounsaturated FA and higher levels of eicosapentaenoic acid. Therefore, the 4-d whole blood FA pattern is associated with both GA and birth weight.     

Brainstem auditory evoked responses in term small for gestational age newborn infants born to undernourished mothers.

Our aim was to assess the effect of intrauterine growth retardation on neurosensory development by evaluating brainstem auditory evoked responses (BAER) in term small for gestational age (SGA) newborn infants born to undernourished mothers. This prospective clinical study included 25 singleton healthy SGA newborn infants born between 38 and 41 weeks to undernourished mothers (weight <45kg, height <145cm, haemoglobin <8g/dl, and serum albumin <2.5g/dl). An equal number of age- and sex-matched appropriate for gestational age newborn infants born to healthy mothers served as controls. Mothers with other risk factors and newborns with complications during delivery or immediate newborn period were excluded. BAER was recorded within first 3 days of life. Interpeak latency (IPL), absolute peak latency (APL) and amplitudes of various waveforms were determined and compared between the groups.No statistically significant differences were observed for the mean interpeak and absolute latencies between term SGA and AGA infants (p>0.05). The absolute peak latency (wave V) and central conduction time (I-V interval) were borderline prolonged in the study group compared with controls (p=0.051 and 0.088 respectively). Using multiple regression analysis, maternal haemoglobin was identified to be the only parameter having a negative correlation with both IPL (waves I-V) (F[1,46]=4.12, p=0.048) and APL (wave V) (F[1,46]=5.80, p=0.02). Maternal undernourishment may have a minor effect on intrauterine development of the auditory brainstem. Maternal haemoglobin is the only factor significantly associated with these changes.     

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.     

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.     

Fetal growth regulation and intrauterine growth retardation

Gestational age and neonatal anthropometric parameters are currently used to evaluate fetal growth and are predictive factors of perinatal and postnatal morbidity and mortality. We performed a retrospective analysis of neonatal anthropometric parameters (weight, vertex-heel length and head circumference) in 1,470 live preterm neonates born between 1997 and 2002 and a prospective analysis of the same parameters in 1,786 live newborns of both sexes born in 2001 and 2002, products of single 37-42 week uncomplicated pregnancies in healthy Spanish Caucasian mothers. A progressive increase in these parameters with gestational age and sexual dimorphism were observed from the 30th week of gestational age onwards, with statistically-significant differences (p<0.05) at 38-42 weeks of gestational age. An increase in weight and length values in relation to previous Spanish studies was also documented in preterm newborns. It is estimated that 10-15% of children born small for gestational age (SGA) do not experience catch-up growth by the age of 3 years and may have short stature in adulthood. Preliminary data of a cross-sectional study on spontaneous growth in boys and girls born SGA without postnatal catch-up growth show that their +2 SD values of height are similar to -2 SD values of our normal control population of children born with adequate weight and length for gestational age (AGE). However, weight +2 SD values are similar to mean values of control children born AGE. In summary, our data show sexual dimorphism in neonatal anthropometric growth parameters and that these parameters change with time and may be updated. In addition children born SGA without postnatal catch-up are shorter and have higher weight than age-, height- and sex-matched controls born AGE.     

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.     

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.