A new population-based reference for gestational age-specific size-at-birth of Singapore infants

<p><b>INTRODUCTION</b>There is currently a lack of representative data for local gestational age-specific size-at- birth percentile charts. Existing charts also suffer from limitations relating to the measurement of gestational age (GA) and an outdated population. We aim to construct reference values and charts for size-at-birth from 35 to 41 weeks, based on the healthy local population.</p><p><b>MATERIALS AND METHODS</b>Prospective observational birth cohort study which recruited pregnant mothers from the 2 major public hospitals with obstetric service in Singapore, at <14 weeks gestation and data was collected for birth weight, length and head circumference of infants born from November 2009 to May 2011. Percentile curves were created separately for male and female infants using the lambda-mu-sigma (LMS) method. The new percentile curves were then compared with other internationally published growth charts.</p><p><b>RESULTS</b>Smoothened curves for birth weight, length and head circumference centiles were created from 863 infants (460 males, 403 females). Male infants consistently exceeded female infants in all 3 variables at each GA. For a male and female Singapore infant at 38 weeks gestation, the 10-50-90th centile values for weight would be 2663-3096-3597 vs. 2571-2966-3417 grams, for length 46.4-48.6-51.1 vs. 45.6-48.0-50.4 cm, and for head circumference 32.0-33.5-35.2 vs. 31.4-32.9-34.6 cm. There was no statistically significant difference between ethnic groups. On comparing our birth weight curves with data from Finland across all gestations, birth weights in our term infants (GA ≥37 weeks) were found to be lower across the 10-50-90th percentiles.</p><p><b>CONCLUSION</b>The new centile charts in this study may be used as reference charts for size-at-birth for a subgroup of near-term and term infants. The use of foreign charts may lead to misclassification of small for gestational age (SGA) or large for gestational age (LGA) infants.</p>

The methodology of the GUSTO cohort study: a novel approach in studying pediatric allergy

Growing Up in Singapore Towards healthy Outcomes (GUSTO) is Singapore's largest birth cohort study to date. The main aim of GUSTO is to evaluate the role of developmental factors in the early pathways to metabolic compromise. Detailed data is collected for a range of environmental exposures in the parents and offspring, and allergic disorders are among a number of outcomes assessed in infancy and childhood. Under the Allergy domain of GUSTO, this integrated study will describe the epidemiology of allergic manifestations and different phenotypes in the Asian context and help shed light on the association of metabolic disease to allergy. Epigenetic mechanisms and associations with other childhood disorders will also be explored. The aim of this report is to focus on methodology of GUSTO, and to suggest similar approaches (i.e., integrated cohort studies on pediatric allergy) worldwide. Recruitment commenced in 2009 with a cohort of 1,163 pregnant mothers in their first trimester. The mothers and children were followed throughout pregnancy and follow-up will continue until the child reaches 3 years of age. Preliminary results showed that 39.8% of the mothers had a personal history of having at least one allergic disease, which included asthma, eczema and allergic rhinitis. Further data collection and analyses are still ongoing. Allergy is a complex spectrum of disorders with numerous poorly-understood aspects. The ongoing GUSTO cohort study, with its longitudinal design and multi-disciplinary nature, may provide new insights into developmental influences on allergy. As a Singapore-based study, it will be the first integrated allergy cohort in Southeast Asia, of which recruitment started during pregnancy.