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Background Birthweight centiles beyond the traditional thresholds for small or large babies are associated with adverse perinatal outcomes but there is a paucity of data about the relationship between birthweight centiles and childhood development among children born from 37 weeks of gestation. This study aims to establish the association between birthweight centiles across the whole distribution and early childhood development among children born from 37 weeks of gestation. Methods and findings This is a population-based cohort study of 686,284 singleton infants born from 37 weeks of gestation. The cohort was generated by linking pregnancy and delivery data from the Scottish Morbidity Records (2003 to 2015) and the child developmental assessment at age 2 to 3.5 years. The main outcomes were child's fine motor, gross motor, communication, and social developmental concerns measured with the Ages and Stages Questionnaires-3 (ASQ-3) and Ages and Stages Questionnaire: Social & Emotional-2 (ASQ:SE-2), and for a subset of children with additional specialist tools such as the Modified Checklist for Autism in Toddlers (M-CHAT) if the ASQ3/SE indicate these are necessary. The ASQ score for each domain was categorised as 'concern' and 'no concern.' We used multivariate cubic regression splines to model the associations between birthweight centiles and early childhood developmental concerns. We used multivariate Poisson regression models, with cluster robust errors, to estimate the relative risks (RRs) of developmental concerns below and above the established thresholds. We adjusted for maternal age, early pregnancy body mass index (BMI), parity, year of delivery, gestational age at delivery, smoking history, substance misuse in pregnancy, alcohol intake, ethnicity, residential area deprivation index, maternal clinical conditions in pregnancy (such as diabetes and pre-eclampsia), induction of labour, and child's sex. Babies born from 37 weeks of gestation with birthweight below the 25th centile, compared to those between the 25th and 74th centile, were at higher risk of developmental concerns. Those born between the 10th and 24th centile had an RR of 1.07 (95% CI: 1.03 to 1.12, p < 0.001), between the 3rd and 9th centile had an RR: 1.18 (95% CI: 1.12 to 1.25, p < 0.001), and The percentage of developmental concerns attributable to birthweight between the 10th and 24th centile was more than that of birthweight Conclusions We observed that from 37 weeks of gestation birthweight below the 25th centile was associated with child developmental concerns, with an association apparent at higher centiles above the conventional threshold defining small for gestational age (SGA, 3rd or 10th centile). Mild to moderate SGA is an unrecognised potentially important contributor to the prevalence of developmental concerns. Closer surveillance, appropriate parental counselling, and increased support during childhood may reduce the risks associated with lower birthweight centiles., Author(s): Abiodun Adanikin 1,2,*, Deborah A. Lawlor 3,4, Jill P. Pell 5, Scott M. Nelson 6, Gordon C. S. Smith 7, Stamatina Iliodromiti 2,* Introduction Low and high extremes of [...]

Lamb survival in Australian Merino sheep was investigated using survival records from 14,142 lambs born between 1975 and 1983. This data set included roll calls of live lambs at birth, 7 d, marking (30 d), and weaning (110 d), which allowed 4 binomial traits (alive or dead) to be recorded for each lamb at each time interval. The average survival to weaning was 72.4% with 23% of singles, 32% of twins, and 45% of multiple-born lambs not surviving to weaning. The timing of lamb loss was consistent across birth types; 6% died within 24 h of birth, a further 14% by 7 d, 3% between 7 and 30 d, and 8% between 30 and 110 d. Partitioning of phenotypic variation revealed that after the first postpartum week, mothering ability of Australian Merino ewes is not an important factor in lamb survival. Some ewes repeatedly lose lambs at birth and in the early postnatal period, but the intraclass correlation decreased by a factor of 10 for survival after 7 d of age (0.096 at birth and 0.100 at 7 d, falling to 0.009 at marking and 0.018 at weaning). This study examined the relationships of lamb survival with lamb birth weight and found varying relationships at each time period. Whereas birth weight had a highly significant curvilinear relationship with survival to weaning, the relationship was flatter for survival to 24 h with only small differences between average birth weights and the birth weight at which survival was optimized (-0.04, 0.28, and 0.54 kg for single-, twin-, and multiple-born lambs, respectively). This suggests that any management interventions to increase birth weight may increase the risk of death to both lamb and ewe during the lambing process due to dystocia. Among twin-born lambs there was a carryover effect of losses at birth on subsequent loss in the first week of life. Survival to 7 d of age was highly dependent on the survival of the littermate, favoring those whose littermate survived, but after the first week, this trend was reversed. Lamb birthcoat score had a small positive impact on survival only at birth. Key words: birth weight, lamb survival, Merino sheep

Objectives: To assess the effect of birth weight, length and ponderal index at birth on body mass index (BMI) and skinfold thickness in early adolescence. Subjects/Methods: Population-based, prospective birth cohort study in Pelotas, Brazil. Out of 5249 cohort members, 87.5% were traced at 11 years of age. Birth weight, length and ponderal index (birth weight/birth [length.sup.3] x 100)-treated as continuous variable and divided into fourths--were the exposure variables. BMI at 11 years, triceps and subscapular skinfolds were the outcomes. Confounders included sex, gestational age, parity, maternal schooling, family income, maternal smoking during pregnancy and maternal BMI. Results: All three exposure variables were significantly associated with BMI in early adolescence, but the strongest effect was observed for birth weight. Each unit (Z-score) increase in birth weight was associated with 0.46 kg [m.sup.-2] increase in BMI at 11 years. The equivalent coefficients for ponderal index and birth length were 0.22 and 0.21 kg [m.sup.-2], respectively. High birth weight, length and ponderal index were also associated with increased values for triceps and subscapular skinfolds at 11 years, and with increased prevalence of obesity. Conclusions: Of the three birth exposures studied, birth weight presented the strongest effect on anthropometry in early adolescence. Ponderal index, a proportionality indicator associated with infant mortality, hospitalizations and anthropometry in infancy, was also associated with anthropometry in early adolescence, but its predictive value for the latter is lower than that of birthweight alone. All three birth size indicators studied presented poor predictability of the later risk of obesity. doi:10.1038/ejcn.2008.20; published online 27 February 2008 Keywords: body mass index; body size; skinfold thickness; cohort studies; adolescence; prospective studies, Introduction Weight and length at birth and during the first years of life are associated with the risk of morbidity and mortality both in the short and in the long [...]

The objectives of this study were 1) to estimate the heritability of lamb survival and growth in the Scottish Blackface breed; 2) to examine the relationship between lamb survival and live BW; and 3) to investigate the possibility of using lamb survival in a breeding program for this breed. The data used for the analyses contained information about survival and live BW at different ages on 4,459 animals. The records were collected from 1988 to 2003 in a Scottish Blackface flock. Live BW was recorded every 4 wk from birth to 24 wk. Survival was defined either by perinatal or postnatal mortality (up to weaning at 12 wk), or as cumulative survival to 1, 4, 8, and 12 wk. The pedigree file comprised 1,416 dams and 178 sires. A sire model was used to estimate genetic parameters for binary survival traits. Heritabilities of BW traits, and phenotypic and genetic correlations between BW and between survival and BW were estimated by fitting an animal model. Further, correlations of survival with live BW were estimated by using a Markov chain Monte Carlo threshold model, implemented by Gibbs sampling. The heritability estimates for cumulative lamb survival declined from birth onward (from 0.33 to 0.08), and postnatal survival had a heritability of 0.01. The direct and maternal heritabilities for BW traits ranged from 0.08 to 0.26 and from 0.06 to 0.21, respectively, whereas the maternal environmental component was between 0.04 and 0.16. The genetic correlations between BW traits at different ages were high. The genetic and phenotypic correlations between survival and BW were always positive (ranging from 0.04 to 0.54), so there was no antagonism between these traits. Therefore, it is possible to simultaneously improve both survival and live BW in a breeding program for this breed. Key words: binary trait, genetic parameter, lamb survival, live weight

Relation of birth weight, maternal child rearing behaviors, and maternal intelligence on the cognitive performance of 2-year-old Jamaican children was studied. Results showed low weight infants are less sensitive to maternal behavior and intelligent mothers strongly influenced the child's cognitive behavior.

The study aims to perform a systematic review of the association between birth weight and total blood cholesterol levels, and to explore the impact of including unpublished results, adjusting for potential confounders. A systematic review indicates that any effects of impaired fetal growth on blood cholesterol levels are weak, and unlikely to influence materially the risks of vascular disease in the population.

Using data from the National Longitudinal Survey of Adolescent Health (Add Health), I investigate the relationship between birth weight and cognitive development among adolescents aged 12-17. Initial OLS regression models reveal a significant, positive relationship between low birth weight and verbal ability. Controlling for demographic, socioeconomic, and other adolescent characteristics modifies, but does not eliminate, this relationship. Additional models that stratify the sample by parental education illustrate the greater importance of other family and adolescent characteristics for cognitive development in adolescence, and a diminished role of birth weight. In the final section of the paper, fixed effects models of non-twin full siblings indicate no significant association between birth weight and verbal ability, suggesting that traditional cross-sectional models overstate the influence of birth weight for cognitive development in adolescence.

Birth size--weight, length and head circumference--depends on the level of hormones and other biological factors to which the baby is exposed during pregnancy. Since 1990 it has been suggested that [...]