During the four to six month period you can expect your baby to become much more interactive with you, your baby's going to be laughing and squealing at four months, excited to see you. Your baby's going to try to start to roll at four months so you have to be really careful for safety issues, of course you can never leave your baby unattended, but between four and six months you really have to be careful cause your baby can roll off a couch or roll off a bed. A baby usually pivots off of one leg, and flips themselves over, and often times when the baby flips they can't get back the other way, so the baby will start to cry. If they roll from their back to their belly then sometimes their arm gets stuck and they can't push them selves back the other way, so you'll have to go to the crib or the bassinet and physically help them turn over. A baby can't have any loose blankets in the crib at this age because they can wrap them selves up in it. And no loose toys where they can put their face in it for fear of suffocation. Babies are cooing and making sounds, around six months babies start to make that brr, brr, sound, and the mmm sound, they also start to use vowels, like aa, ee, and they're trying to use their vocal chords, not saying words of course yet, but sometimes you think they're trying to clear their throat because they're going, grr, and growling a little bit, and that's just them trying to communicate.
At four months if babies are breast fed they're still exclusively breast feeding, and the American Academy of Pediatrics recommends that you breast feed exclusively until six months. Some babies at four months are very hungry and they need the introduction of solid foods, because they're not getting enough satisfaction from milk or breast milk alone. I find that four months is a little bit early to start solids, not all babies can do it, a baby has to be sitting up in a high chair with a harness, because you don't want them to slip over or tip over while their feeding. A baby has to be able to take the food with a spoon, what I recommend is the parents make rice cereal as a first food, they can buy infant rice cereal in the super market, they mix it with either breast milk or formula, I recommend dipping your finger into the cereal first and just letting the baby lick the cereal off your finger. This way the baby learns just the texture, often times it will just come right back out, the babies don't know what it is, and it's kind of like feeding a cat and their tongue is out a lot and they're just playing with it. But once a baby does well they can start eating rice cereal from a spoon. Rice cereal is the least allergic, so that's why we recommend to start with it first. I also recommend you start it in the evenings before the last night time feed, so if the baby's hungry and waking up frequently during the night time, the baby can start eating the rice cereal first and maybe they'll last a little longer through the night sleeping maybe 5 to 6 hours instead of 3 to 4 hours.
At six months, after they move on from cereals the babies can start having fruits and vegetables. We always recommend hat you start with stage one foods or single pureed foods, you have to make sure there's no lumps or chunks because the babies can choke on it. You always give a baby each new food, and you wait three days, so if you give peaches one day then you wait three days and then you give applesauce, then you wait three days and you give peas, because if you gave a combination of fruits and vegetables, any kind of combination and the baby had an allergic reaction, which is usually a rash, you wouldn't know if the reaction was from the apples or the peaches. At four months old the baby can start having water, if you use a bottle you can just put the water in the baby's bottle, you have to check if the water is fluoridated where you live. In New York City the water is fluoridated so we just use tap water put through a filter, but in other states and other cities it varies, so you have to check. If the water in your neighborhood is not fluoridated you should buy baby water that has fluoride in it, it will help the teeth develop. And finally, when you're introducing solids and water, we do not recommend juice for babies, only water or breast milk, or formula.