Greater length-for-age increases the odds of attaining motor milestones in Vietnamese children aged 5-18 months.

Early childhood malnutrition has been associated with delayed development. Limited data exist however about the timing of developmental delay early in life. We assessed motor milestone (MM) achievement using the World Health Organization's windows of achievement for gross motor milestones. We performed secondary analysis of baseline data of 158 Vietnamese children aged 5-18 months from a randomized community intervention trial. Median age of motor milestone achievement was compared to WHO reported medians. Multivariate logistic regression was used to identify socioeconomic, anthropometric and dietary factors associated with motor milestone achievement during the windows of achievement. Thirty four per cent of the children were stunted. Median age of MM achievement of Vietnamese children lagged by 2.4-3.7 months, compared to the WHO median for all MMs. Greater length-for-age increased the odds for walking with assistance, standing alone and walking alone by more than 3 times. Greater weight-for-age increased the odds by 3.6 for hand-and-knees crawling. Likewise, frequency of daily complementary feeding raised the odds by 3.6 for standing with assistance. In this first application of WHO windows of achievement in Viet Nam, pre-schoolers achieved motor milestones later than WHO reported median age. High prevalence of stunting and association of length-for-age with motor milestone achievement underscore the importance of addressing chronic malnutrition to optimize children's growth and development.