For a 12-month-old baby, growth and development indicators are generally as follows: i. Weight. Boys about 9.87-10.9kg, girls about 9.02-9.24kg. ii. length. About 75.2-76.5cm for boys and 73.7-75.1cm for girls. iii. head circumference. The average head circumference is about 46.3cm for boys and 45.2cm for girls. iv. fontanel. From the age of 6 months, the fontanel of the child will continue to shrink; by 12 months, some children’s fontanel has closed; but some babies will not close the fontanel until about 18 months, all are normal.