It's important to understand how your baby develops so you know what to expect from your child. It's also important to know if your child isn't hitting a developmental milestone as this could signal a problem. If your child isn't hitting the developmental milestones, you should let your pediatrician know so he can decide what the next course of action will be.
Every month your baby goes through dramatic changes. She is learning how the world works around her, how to use her arms and legs, what she likes and what she doesn't like. Her social skills develop alongside her physical skills--she is learning a huge amount in a short amount of time. From day one, she is learning cause and effect; if she moves her leg, she may kick a toy, or if she cries, you appear to make her feel better.
This is a general guide, broken into months. Some babies meet these milestones sooner, others later. If your baby is premature, expect your child to be behind for about a year in her development. Speak to your pediatrician about when you can expect your child to hit her milestones as it can differ depending on how early your child was born. The majority of premature babies hit their milestones according to their adjusted age (around the time they would've if they were born at term).
- One Month. Your baby has just been born and you may think your baby doesn't do anything other than cry, poop, sleep and eat, but your baby is actually doing a great deal more. During the first month your baby's head needs to be supported, because her neck muscles are not strong enough to hold her head upright, though your baby's neck muscles grow stronger every day. Your baby will love snuggling on a loved one's chest for warmth and to hear his heartbeat. At one month old, your baby will recognize her parents' and possibly siblings' voices and be captivated by something as simple as eye contact. She will be able to focus on faces and objects that are 8-14 inches away.
- Two Months. At the end of two months, your baby has changed a great deal. Your baby has learned how to smile. She can make noises other than crying and can lift her head up about 45 degrees. She likes being smiled at and will likely respond with a smile of her own. She will study faces and will even respond to a bell or similar noise by crying, startling or quieting.
- Three Months. By the end of three months, your baby is becoming more mobile. She has learned how to roll side to side and may enjoy playing in tummy time. She will start to laugh and smile at faces. She will have different cries for different needs, a big help if you're uncertain why your baby is crying. Your baby will also know the difference between her parents and strangers, and may respond by crying if left in a stranger's care.
- Four Months. By the end of four months, your baby should be consistently rolling over and reaching for objects. She should be able to lift her head 90 degrees and push away or object to a disliked action; her personality is developing. Your baby should be babbling and turning her head toward speakers. By the end of four months, your baby should be able to sleep through most of the night.
- Five Months. By the end of five months, your baby should be able to hold her head up steadily. She should be able to raise her chest, supported by her arms and pay attention to a small object. She may even be able to reach for an object and hold it.
- Six Months. By the end of six months, your baby has doubled her birth weight. Your baby has learned how to make a wet razzing sound (like a raspberry), and may be able to bear some weight on her legs if held upright. Your baby may even be able to sit up without support. In addition, your baby should be taking two naps a day and sleeping for 10-11 hours at night.
Around five to six months, you will want to talk to your pediatrician about starting solid food, though some people wait until their babies are a little older before starting solid food. Your pediatrician will have recommendations about how to start this process.
- Seven Months. By the end of seven months, your baby should be able to sit without support and perhaps feed herself something small. She has learned what she likes and what she doesn't and will likely object loudly if you take away a toy or an object she's using.
- Eight Months. By the end of eight months, your baby should be able to bear some weight on her legs when held upright. She should be able to pass an object from one hand to the other and turn in the direction of a voice. She will likely look for a dropped toy because she has learned that just because an object disappears doesn't mean it doesn't exist anymore.
- Nine Months. At the end of nine months, she should be able to sit alone, imitate sounds and possibly crawl. Not all babies crawl; some go from rolling to get what they want straight to walking. It isn't a concern if your child skips crawling. At nine months, your baby is probably showing stranger anxiety and trying to figure out how things work.
- Ten Months. Ten months is a fun month and it only gets more fun from here. By the end of ten months, your baby has been working hard to learn how to stand. She will likely be able to go to a standing position from sitting and even stand holding onto someone or something. She will have learned how to say "mama" and "dada," and enjoy playing games like peekaboo.
- Eleven Months. At the end of eleven months, your baby should be able to go to use her arms to go to a sitting position from her stomach, and pick up a tiny object with her thumb and finger. In addition, your baby should be able to understand, though not always obey, 'no.'
- Twelve Months. By the end of your baby's first year, she has probably tripled her birth weight. She should now be able to walk holding onto furniture and has graduated to being a toddler. Your baby plays a great deal, makes lots of noise, and enjoys reading books and playing imitative games with you.
- If you want to learn more about infant development you may want to take an infant or child development class at your local college. Your pediatrician may also have a class or a series he can recommend. There are also many books about infant development including Smart Baby, Strong Baby: Your Baby's Development Week by Week During the First Year and How You Can Help by Penny Warner, Baby Steps, Second Edition: A Guide to Your Child's Social, Physical, Mental and Emotional Development in the First Two Years by Claire B. Kopp and Infant Development (3rd Edition) by Charles W. Snow, Cindy G. McGaha. I've also included a few links about baby development.