Your Baby's Growth: 4 Months

Babies this age continue to grow in size, and in what they can do. Many of the new skills they're learning — like holding their head up and sitting — help them get ready to start eating solid food when they're around 4–6 months old. 

How Much Will My Baby Grow?

By 4 months, many babies have doubled their birth weight. This month, your baby will gain about 1 to 1¼ pounds (450–560 grams) in weight and about 0.8 inches (2 centimeters) in length. But it’s also OK if your baby grows a little more or a little less.

How Is My Baby’s Growth Checked?

Since your baby's birth, the health care provider has recorded your little one's growth in weight, length, and head size (circumference) during your baby’s checkups. By now, you should begin to see a growth curve that shows your baby growing steadily.

Babies who were born early might still be behind in size compared with their full-term peers, but they should also be growing steadily at their own rate.

What Happens if My Baby’s Growth Is Slow?

Is my baby big enough? Is my child going to be tall or short? Parents might worry about growth or compare a baby with siblings and peers. It's important to remember that kids come in a wide range of shapes and sizes. The growth curve they're on now won’t necessarily be the growth curve they stay on.

Growth depends on many things, including:

• genes passed on by the parents (kids tend to resemble their parents in height)
• the amount and type of food a child eats
• overall health
• how well the hormones that control growth work
• whether a child has any medical conditions

Based on your child's growth chart, the health care provider can see if your baby is growing as expected. If they're concerned about your baby's weight or growth, they will ask:

• How many feedings a day does your baby get?
• How much does your baby eat at each feeding?
• How long does a breastfeeding baby nurse at each feeding?
• What else are you feeding your baby?
• How often does your baby poop (have bowel movements)? What does the poop look like?
• How often does your baby pee?

They'll also ask about your baby's health, development, and any illnesses that run in your family, and do an exam. All these things together will help the doctor decide if your baby is growing at the right rate. If needed, they may recommend that you take your baby for tests.

Could My Baby Gain Too Much Weight?

The doctor is tracking your baby’s growth and can tell you if your baby needs to slow down with weight gain. This usually doesn’t happen, but overfeeding a baby or giving extra calories through juice can sometimes make a baby gain too much weight.

Never withhold food or use watered-down formula to try to slow weight gain. Your baby needs proper nutrition, including fat, to grow and develop.

Here are some healthy habits for your baby:

• Stop a feeding when your baby seems satisfied. As long as your baby doesn't have trouble gaining weight, you don’t need to “top off” a feeding with a few extra minutes on the breast or more formula.
• Do not give your baby juice. It adds extra calories without the balanced nutrition in formula and breast milk. Drinking too much juice also may lead to excess weight and tooth decay, or cause diarrhea in infants and toddlers.
• Feed your baby when they seem hungry. But be aware that sometimes when your baby fusses or cries, it's not a sign of hunger. They might just want to play or be with you.
• When you do start solid foods (when your baby is 4–6 months old), talk to the health care provider about which foods to give and how much. Watch for your baby’s cues that they've had enough (such as acting disinterested, turning their head away, or holding their mouth closed).
• Do not put cereal in the bottle (unless the health care provider told you to). It can cause rapid weight gain and young babies may gag on it or inhale it into their lungs.
• TV, videos, and other types of screen time aren't recommended for babies this young. Video chatting is OK.

When Will My Baby’s Growth Be Checked Next?

Unless your baby needs to come in sooner, the doctor will see your baby and check growth at the 6-month checkup. Your baby will continue to grow at a steady rate. Expect big changes as your baby starts to sit up and move around!

Call the doctor if you have any concerns about your baby’s growth or health.