Your 4-month-old baby is past her newborn days and entering a phase in her life where she is alert to the world around her and developing the mobility she needs to explore it. Although all babies grow and develop at various paces, most also gain weight and height at a remarkable pace in the first half year of life.
Growth
From the time your baby was born until now, he has likely gained between 1.5 and 2 lbs. a month, according to KidsHealth. He should keep up this trend until he is about 6 months old, when his growth will slow to 1 to 1 ¼ lbs. every month until he is a year old. He should also grow ½ inch to 1 inch per month until he reaches his sixth month, when he will start to gain in height at a more leisurely pace of about 3/8 inch per month.
Growth Factors
Your baby will grow at her own pace. If her growth is slower or faster than that of her peers, she may have inherited that pattern from you or she may be genetically predisposed to short or tall stature. Other factors that may influence her growth are the type and amount of food she eats, her health and how growth hormones in her body are functioning.
Decoding Growth Charts
Your doctor will use a chart to assess your baby's growth from check-up to check-up. If she tells you your baby is in the 60th percentile for weight, it means that your baby weighs as much as, or more than, 60 percent of babies of his gender and age in the United States; it also means he weighs less than 40 percent. Your doctor won't necessarily be concerned that your baby is "too big" or "too small," as long as your baby is growing at a steady pace. However, she might want to do further testing if your baby suddenly dips from the 60th percentile to the 10th percentile for weight.
Physical Milestones
By 4 months, your baby should be using her arms and legs with more purpose and she may be able to rock on her stomach. Keep the camera out, because she might be rolling over soon. Every day she is able to control her head a little better, too; 4 month olds can generally raise their heads when they are lying on their stomachs, according to MayoClinic.com. She is also strong enough to grasp objects and put them in her mouth.
Promoting Healthy Growth
Encourage your 4 month old to grow into a strong and healthy body by giving him plenty of opportunities to play outside his stroller or bouncer. Allow him to reach, roll and scoot on the floor. Active time will also allow you to observe him for signs of delays, such as body stiffness or extreme floppiness, lack of head control, and not grabbing or putting toys in his mouth. Now is the time to monitor your own diet and exercise, too. If your baby doesn't observe physical activity and healthy eating from a young age, he is more likely to become overweight.
