RESUMO
The timing of milestone is influenced by many factors. Sex and socioeconomic status has significant effect to some psycomotor milestones. The study was conducted to determine the pattern of milestones of development of infants in our country and to compare it in different sex and socioeconomic condition. It was a hospital based prospective study done in Sir Sallimullah Medical College and Mitford Hospital, Dhaka, Bangladesh from October 2014 to November 2015. Healthy term newborn infants with average birth weight were included in this study and milestones of this birth cohort were assessed monthly from birth to 12 months of age by using a set of 60 milestones. Total number of 217 babies was enrolled but during follow up 0.9% developed meningitis, 43.7% was lost to follow up and 55.2% of the cohort was followed up to 12 months of age. Among 120 babies 51.7% were male, 48.3% were female babies and 51.7% belong to lower, 32.5% middle and 15.8% upper socioeconomic group. There was no significant difference between male and female infants achieving most of the milestones of development except in language development in which female infants were little bit higher than male infants.