Babies grow and develop at a rapid pace during the first year. Their weight doubles by six months and triples by the time they are one year old, according to the March of Dimes. They start as helpless infants only to blossom into toddlers who walk and talk, sometimes to their parents' surprise. Each baby is very different. While there are guidelines for growth and development for early diagnosis of problems, the milestones are not rigid and can vary from child to child.
Motor Skills
By the end of a baby's first two months, he is able to turn his head and lift it slightly while lying on his back. Basic reflexes, like rooting and sucking, are fully developed, and he tightly grips fingers or other objects in his palm. At the end of his fourth month, he tries to grab objects within his reach, although he is not coordinated enough to grasp them yet. When lying on his stomach, he pushes with his arms to raise his head, shoulders and upper torso, and he should have better control of his neck muscles, allowing him to sit with support.
At six months, the baby can grasp some objects, roll from his back to his stomach, sit alone for short periods without support and start to creep or crawl. By nine months old, he is able to sit without support for much longer periods, drink from a sippy cup, pull himself into a standing position while holding onto objects, walk while holding an adult's hands and sit down from a standing position. By the time they reach their first birthday, many babies are able to stand or walk without assistance.
Sensory Development
By the one-month mark, your baby will respond to sounds and stare at faces, and can distinguish between objects that are black or white. Two-month-olds begin to track moving objects, and vocalize, making gurgling sounds. If she did not smile or laugh during her first month, she should in her second month. At four months of age, she may imitate sounds and coo when you talk to her. When she reaches the five- and six-month stages, she will turn her head toward new sounds and start babbling. When your baby reaches the 10-month mark, she may say simple words, like mama and dada, to the correct parent. By her first birthday, her vocabulary may have expanded to include a few additional words.
Cognitive Development
At three months old, babies can recognize a person's face, scent and voice. By five months old, he recognizes his own name and may start to develop separation anxiety. At seven months old, your baby may start to develop stranger anxiety and begin to understand that people and things are still there even though he cannot see them, making a game of peek-a-boo one of his favorites. When he reaches eight months old, he will start to point at objects and look for things you hide. He may also begin to try to communicate what he wants with gestures. By 11 months old, he understands the word no, as well as other simple instructions. Once he reaches his first birthday, he may begin to imitate the activities and gestures of other people.
