Children's Age-by-Age Guide: Birth to 3 Months

Physical Milestones

As a new parent, you've no doubt been watching your little one very closely. You may have noticed that she lost a few ounces in the first few days of life. Not to worry: most babies regain their birth weight within two weeks and continue gaining 6 to 8 ounces a week for the next few months. At each well-baby checkup your pediatrician will chart your child's length, weight, and percentile growth rate (how she compares with other babies her age). Keep in mind that the exact percentile isn't as important as seeing that a baby doesn't suddenly drop to a much lower percentile. Length measurements shouldn't be taken too seriously either, since measuring a squirmy infant is a tough task.

Breast-fed babies tend to nurse every 2 to 3 hours, spending about 10 minutes per breast, while bottle-fed babies usually eat every 3 to 4 hours (taking 2 to 4 ounces at a feeding). Either way, babies need to be fed at least six times in a 24-hour period.

How can you tell if your baby is eating enough? If a bottle-fed baby is gaining weight, then she is thriving. Depending on their size, growth rate, activity level and metabolism, bottle-fed babies take in varying amounts of formula. On average, a 2-month-old will take 28 ounces a day. Don't worry: your baby will let you know when she's had enough. Just don't try to force-feed her. For breast-fed babies, weight gain isn't the only way to know your little one is getting enough nourishment. If she is having several yellowish bowel movements a day in the early weeks, her diaper is wet regularly, you hear a lot of gulping and swallowing when she nurses, and she seems content after feeding, then she's probably getting enough.

Smart Strategy:

The American Academy of Pediatrics (AAP) recommends that healthy babies always be put on their backs to sleep since back sleeping has been found to significantly reduce the risk of Sudden Infant Death Syndrome (SIDS). Here are other ways to reduce your baby's risk of SIDS:

• Use a firm, flat crib mattress. Waterbeds, beanbags, futons pillows, and sofa cushions should never be used as sleeping surfaces.
• Keep loose bedding and stuffed toys out of your infant's crib. Quilts, blankets, sheepskins, lambskins or comforters can block air circulation.
• Ban smoking around your baby.
• Teach babysitters, daycare workers, and grandparents to put your little one to sleep on her back, even at naptime.
• Make sure your baby receives all scheduled vaccines.

Developmental Milestones

Newborns generally sleep an average of 7 hours at night and 8 hours during the day. At night, they sleep in cycles of 3 or 4 hours, moving from a light, dreamy state to a deep sleep, then back to light snoozing. Babies may wimper, suck, cry out, or make fussy noises at times. If you respond to all your child's awakenings, he'll become dependent on your help to get back to sleep. Be there to comfort him with your voice, but unless he is really crying, allow him to fall back asleep on his own. How to get a baby to sleep is one of the greatest debates in childrearing.

Smart Strategy:

The way your newborn moves from sleep to awake states (either gradually or suddenly) will clue you in to his temperament (active, quiet, or average). When your baby has had enough stimulation and becomes overloaded, he'll need your help to quiet down by swaddling, holding, or singing to him. A quiet baby will need more stimulation from you to get him involved in his world while an active baby will most need help in calming down.

Right now, your newborn is learning to be attentive and focus her senses. She'll look into your eyes, be absorbed by your voice and expressions, and may even try to imitate you. By 2 or 3 months, she'll smile and respond to your joy in her-you'll both be falling in love.

Smart Strategy:

Don't hesitate to pick up your infant whenever she cries. You can't spoil her at this age. She needs your constant support to develop.

Cognitive Milestones

Crying is your baby's language and soon you'll be able to distinguish cries of pain, hunger, and fear, which will help you become a more confident parent. He'll turn his head when he hears your voice and he'll react to noise, motion, and light.

Smart Strategy:

Expose your baby to different stimuli such as soft toys, music, and the outdoors so he becomes more aware of his surroundings.

• Birth to 2 months -- The first of three doses of the Hepatitis B (Hep B) vaccine should be given by age 2 months. The second dose should be administered at least one month after the first dose.
• 2 months -- Diphtheria, Tetanus, Pertussis (DtaP)
• 2 months -- H. influenzae type b (Hib)
• 2 months -- Inactivated polio (IPV)
• 2 months -- Pneumococcal conjugate (PCV)