The first thing everyone wants to know when a baby is born (other than what's his name?) is how much he weighed and how big he was. You're certainly going to want to continue charting his growth after that initial weigh-in.

What's more notable are the developmental milestones that infants achieve in their first year of life. It's an amazing journey, encompassing gross and fine motor skills, sensory awareness, language, and social development. These milestones really are worth charting, if you want to remember how your baby grew in that first phenomenal year.

Measuring Your Baby

Your pediatrician will surely keep track, but it's also easy to measure and weigh your baby at home between check-ups. You can measure his weight by getting on the scale, then weighing yourself again while holding him. You can measure his length from the crown of his head to the bottom of his heel. Wrap a soft tape measure around the largest part of his head to measure head circumference.

To find out how your baby stacks up against his peers, plug all these numbers into an online growth chart. Keep in mind that most growth charts are based on national averages for bottle-fed babies. If you're nursing, look for charts for breastfed babies, who tend to grow more slowly.

But what does it mean if your baby falls below the 50th percentile? It means only that he's smaller than half the babies his ageit doesn't indicate ill health or that he's not progressing as he should. All babies are different and develop at different rates. Growth charts are simply a way to track his progress.

Growth Markers

What should you expect throughout year one? Here are some important developmental and growth milestones.

Newborn

Babies lose up to 10 percent of their birth weight during the first days of life but should regain the weight by two weeks and add at least two-thirds of an ounce every day. Most babies also grow one to one-and-a-half inches in length per month.

Two Months

Your baby will melt your heart with smiles that are not about gas. He can laugh and make noises, turn toward sounds, and follow objects at a distance of 12 inches with his eyes. He'll keep her hands in tight fists and bring them near his face. Black-and-white images will stimulate his mind.

Four to Five Months

He'll start to roll over (front to back), bear weight on his legs, sit with support, and raise his head and chest when lying on his stomach. He watches faces closely, will imitate sounds, and enjoys playing with other people. He can open and shut his hands and bring them to his mouth.

Eight Months

By this point, your baby will have probably doubled his birth weight. He can roll over both ways (front to back and back to front), sit up without support, reach for an object and transfer it from hand to hand, and support his weight on his legs when held upright. He'll babble and coo, and try to put objects in his mouth.

Twelve Months

Prepare yourself for mobility! At this age, your baby has probably tripled his birth weight, and can cruise the furniture, holding on while taking steps. He'll combine syllables and make your day by calling mama and dada. He can bang objects together, point to pictures, and use simple gestures, such as waving bye-bye.