126 Malaysian children, 65 boys and 61 girls from higher income families were followed-up regularly from birth to six years of age in the University Hospital, Kuala Lumpur. The study confirms the observations of previous studies that growth velocity of head circumference is most rapid during the first few months of infancy and then decreases so that by the fifth year of life the increment is minimal. It also confirms the fact that boys have bigger head circumferences than girls. The paper also presents the head circumference distance and velocity percentile charts which can be used to monitor the head circumference of Malaysian children.
Over an 18 month period, 34,495 livebirths were delivered in the Kuala Lumpur Maternity Hospital. 36 neonates (1.044 per 1000 livebirths) had Down's syndrome. The observed rates of Down's syndrome per 1000 livebirths by single year intervals of maternal age were calculated. By using the discontinuous slope model, our study showed that the incidence of Down's syndrome among the Malaysian liveborns increased markedly when the maternal age exceeded 35 years. This study also suggested that the Malay mothers had increased risk of producing babies with Down's syndrome at a later age than the Chinese and the Indians. However, a larger number of babies in each racial group needs to be studied to confirm this.