Your Baby's Growth: 1 Month

Babies grow quickly in both weight and length this month.

How Much Will My Baby Grow?

Your baby will gain about 1 to 1½ inches (2.5–3.8 centimeters) in length this month and about 2 pounds (907 grams) in weight. But it’s also OK if your baby grows a little more or a little less.

At this point, you're learning the signs that your baby is hungry or full. When hungry, your baby may seem restless, cry, stick out their tongue, or suck on their hands and lips. When full, your baby probably doesn't seem interested in feeding or just falls asleep after feeding.

Your baby may go through periods of increased hunger and fussiness. This increase in hunger means your baby is going through a period of fast growth (a growth spurt). If you breastfeed, you might find your baby wants to eat more often (sometimes every hour!) during certain times of the day. This is called "cluster feeding." Formula-fed babies may want to eat more often or will drink more formula than usual during feedings.

How Is My Baby’s Growth Checked?

At your baby’s checkups, the health care provider measures your baby's weight, length, and head circumference. They put this information into a growth chart (there are different charts for boys and girls). The growth chart lets them see if your baby is growing at the right pace. Whether your baby is big or small for their age now doesn’t necessarily mean they will be big or small when they are older. What matters most is that your baby is growing steadily.

Babies who were born prematurely may need special formula or “fortifiers” added to the formula to give more nutrients and calories. Doctors may want to check growth more often during the first few months to make sure the baby is growing enough. It can take a while for babies born early to catch up, but as long as they are growing steadily, it’s usually OK.

What Happens if My Baby’s Growth Is Slow?

If your baby isn’t growing at an expected pace, the health care provider will check your baby and ask you about:

• how many feedings a day your baby gets: At 1 month, a breastfed baby may feed about 8 times in a 24-hour period (roughly every 2–3 hours); bottle-fed babies usually eat less often, perhaps every 3–4 hours.
• how much your baby eats at each feeding: A baby generally nurses for at least 10 minutes, should be heard to swallow, and should seem satisfied when done. Bottle-fed babies may drink up to 4–5 ounces (118–148 milliliters) at a time.
• how often your baby pees: Babies should have at least 4–6 wet diapers a day.
• how many bowel movements (BMs or poops) your baby has each day and if they are firm or runny: The number of poops can vary a lot. Some breastfed babies poop with every feeding, but they also might not poop for a day or more. Most formula-fed babies poop at least once a day but others poop more or less than that. Breastfed babies' stools tend to be soft and slightly runny. The stools of formula-fed babies tend to be a little firmer. Whether your baby is breastfed or formula-fed, their pooping pattern is probably OK as long as the poop is not hard and doesn't have mucus or blood in it.

They'll make some recommendations to be sure your baby gets enough to eat. If you breastfeed, it might help to see a lactation consultant. They can answer any questions you have and make sure your baby gets enough breast milk.

The health care provider may want to see your baby sooner than the next regular checkup, just to make sure your little one is growing OK.

Could My Baby Gain Too Much Weight?

Your baby will keep growing quickly for the next few months. You don’t need to worry about your baby gaining too much weight at this age, so feed your baby whenever they seem hungry.

Still, it’s OK to start some healthy habits with 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.
• Babies this age shouldn’t have juice, cereal, or other foods. They get the nutrition they need from breast milk or formula. Also, starting juice or foods early can cause them to gain too much weight.

Babies this age don’t need extra water. Never water-down formula to try to slow weight gain.

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 2-month checkup.

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