While all babies may grow at a different rate, the following is the average for boys and girls 4 to 6 months of age:
Weight: average gain of 1 to 1¼ pounds each month; by 4 to 5 months has doubled birthweight
Height: average growth of ½ to 1 inch each month
Head size: average growth of about ½ inch each month
This age is very social and babies start moving in much more purposeful ways. Babies may progress at different rates, but these are some of the common milestones your baby may reach in this age group:
Grasp, Moro, root, and tonic neck reflexes (reflexes normally present in young infants) disappear
Balances head well
Sits with support, back is rounded
Starts to support body with legs when held in standing position
Rolls from back to front and front to back by 6 months
Moves object from one hand to other
Grabs feet and toes when lying on back
Makes "swimming" motions with arms and legs when placed on abdomen
Starts drooling (not always a sign of teething)
Naps 2 to 3 times a day, for 1 to 3 hours each (on average)
Starts to sleep longer at night (6 to 8 hours consistently)
Has full color vision, able to see at longer distances
It is very exciting for parents to watch their babies become social beings that can interact with others. Every baby develops speech at his or her own rate, but these are some of the common milestones in this age group:
Coos and gurgles when talked to, or in response to toys
Babbles, imitates sounds
By 6 months, makes single syllable sounds (da, ma, ba)
Blows bubbles or "raspberries"
A baby's awareness of people and surroundings increases during this time and he or she may start to interact with people other than parents. Babies may progress at different rates, but these are some of the common milestones in this age group:
Recognizes familiar things and people
May hold out arms to be picked up
Begins to learn concept of object permanence (such as a partially hidden object under a blanket is still there)
May show displeasure when object or person goes away
May recognize his or her own name
May start to understand "no"
Starts to understand cause and effect (the sound a toy makes when it is dropped)
Consider the following as ways to foster the emotional security of your baby:
Repeat sounds and smile when your baby makes sounds.
Laugh with your baby.
Talk to and imitate your baby during feeding, dressing, changing diapers, and bath time.
Spend time on the floor playing with your child every day.
Dance with your baby and do other rhythmic movements.
Introduce your baby to other children and parents.
Place safe toys near your baby to encourage reaching and grasping.
Encourage laughing and play by making funny faces or sounds or blowing on baby's belly and laughing.
Play peek-a-boo games to help develop object permanence, the understanding that objects are still present even though they can't be seen.
Show your baby bright picture books and interesting objects.
Show your baby his or her reflection in a mirror.
Read books and stories to your baby, and point out pictures.
Take your baby outside to see new things and people.
Hold your baby for feedings and cuddle when he or she is awake.
Hold and comfort your baby when he or she is unhappy.