Thorough training, continuous standardization, and close monitoring of the adherence to measurement procedures during data collection are essential for minimizing random error and bias in multicenter studies. Rigorous anthropometry and data collection protocols were used in the WHO Multicentre Growth Reference Study to ensure high data quality. After the initial training and standardization, study teams participated in standardization sessions every two months for a continuous assessment of the precision and accuracy of their measurements. Once a year the teams were restandardized against the WHO lead anthropometrist, who observed their measurement techniques and retrained any deviating observers. Robust and precise equipment was selected and adapted for field use. The anthropometrists worked in pairs, taking measurements independently, and repeating measurements that exceeded preset maximum allowable differences. Ongoing central and local monitoring identified anthropometrists deviating from standard procedures, and immediate corrective action was taken. The procedures described in this paper are a model for research settings.

Measurement and standardization protocols for anthropometry used in the construction of a new international growth reference.

The objective of the Motor Development Study was to describe the acquisition of selected gross motor milestones among affluent children growing up in different cultural settings This study was conducted in Ghana, India, Norway, Oman, and the United States as part of the longitudinal component of the World Health Organization (WHO) Multicentre Growth Reference Study (MGRS) Infants were followed from the age of four months until they could walk independently Six milestones that are fundamental to acquiring self-sufficient erect locomotion and are simple to evaluate were assessed: sitting without support, hands-and-knees crawling, standing with assistance, walking with assistance, standing alone, and walking alone The information was collected by both the children's caregivers and trained MGRS fieldworkers The caregivers assessed and recorded the dates when the milestones were achieved for the first time according to established criteria Using standardized procedures, the fieldworkers independently assessed the motor performance of the children and checked parental recording at home visits To ensure standardized data collection, the sites conducted regular standardization sessions Data collection and data quality control took place simultaneously Data verification and cleaning were performed until all queries had been satisfactorily resolved

Assessment of gross motor development in the WHO Multicentre Growth Reference Study.

Background Evidence exists that normal gestational length varies with ethnicity. This UK-based study compares gestational length amongst a cohort of white European, Black and Asian women. Methods The cohort comprised 122 415 nulliparous women with singleton live fetuses at the time of spontaneous labour, giving birth in the former North West Thames Health Region, London, UK. Results The median gestational age at delivery was 39 weeks in Blacks and Asians and 40 weeks in white Europeans. Black women with normal body mass index (BMI) (18.5-24.9 kg/m(2)) had increased odds of preterm delivery (odds ratio [OR] = 1.33, 95% CI: 1.15, 1.56, adjusted for deprivation and BMI) compared with white Europeans. The OR of preterm delivery was also increased in Asians compared with white Europeans (OR = 1.45, 95% CI: 1.33, 1.56, adjusted for single unsupported status and smoking). Meconium stained amniotic fluid, which is a sign of fetal maturity, was statistically significantly more frequent in preterm Black and Asian infants and term Black infants compared with white European infants. Conclusions This research suggests that normal gestational length is shorter in Black and Asian women compared with white European women and that fetal maturation may occur earlier.

Does gestation vary by ethnic group? A London-based study of over 122 000 pregnancies with spontaneous onset of labour

The World Health Organization (WHO) Multicentre Growth Reference (MGRS) data management protocol was designed to create and manage a large data bank of information collected from multiple sites over a period of several years Data collection and processing instruments were prepared centrally and used in a standardized fashion across sites The data management system contained internal validation features for timely detection of data errors and its standard operating procedures stipulated a method of master file updating and correction that maintained a clear trail for data auditing purposes Each site was responsible for collecting entering verifying and validating data and for creating site-level master files Data from the sites were sent to the MGRS Coordinating Centre every month for master file consolidation and more extensive quality control checking All errors identified at the Coordinating Centre were communicated to the site for correction at source The protocol imposed transparency on the sites data management activities but also ensured access to technical help with operation and maintenance of the system Through the rigorous implementation of what has been a highly demanding protocol the MGRS has accumulated a large body of very high-quality data (authors)

Managing Data for a Multicountry Longitudinal Study: Experience from the WHO Multicentre Growth Reference Study

Learning to walk is one of the great achievements in human development. An aim of this chapter is to describe the developmental progression of locomotion, ranging from the spontaneous leg kicks of fetuses to the seemingly superhuman abilities of Tarahumaran endurance runners. Our chief aim, however, is to use the development of walking as an exemplar and metaphor for understanding development more broadly. The century-old study of the ontogeny of walking—from the classic descriptions of motor milestones to the modern recognition of the importance of experience in all forms of locomotion—provides one of the clearest, empirically based illustrations of the pragmatic and theoretical issues, methodological advances and conceptual pitfalls, and general principles and processes of development that is available to psychology.

The road to walking: What learning to walk tells us about development.

A prospective study of 320 Nigerian children was undertaken to determine their pattern of motor development by recording the age at attainment of 12 gross-motor milestones. The children were all born full term and were neurologically normal at birth. They were recruited in the first week of life and seen at regular intervals in a well-baby clinic, where their parents were questioned about the ages at attainment of milestones. Results show that most gross-motor milestones were attained at earlier ages by these children than by children studied to establish norms for the traditional tests of motor development that have long been in use. Our findings confirm several previous reports which emphasize the more rapid attainment of motor milestones such as 'sit without support', 'crawl', 'stand well alone' and 'walk well alone' by black as compared with white children. But, conversely, a number of transitional milestones such as 'roll over', 'pull self to stand' and 'stand holding on' were achieved later by children in this study than by their non-African counterparts. Girls in this study were slightly advanced, relative to boys, in their attainment of most milestones. The results of this study have been incorporated into a chart which can be used in well-baby clinics to detect children with motor delay.

W N Kaine

Papers

Gross motor development of Nigerian children.