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Your Baby's Growth: 1 Month

Reviewed by: Cristy A. Wong, MD

Babies continue to grow quickly in both weight and length this month.

How Much Will My Baby Grow?

The first month of life was a period of rapid growth. Your baby will gain about 1 to 1½ inches (2.5 to 3.8 centimeters) in length this month and about 2 more pounds (907 grams) in weight. These are just averages — your baby may grow somewhat faster or slower.

Your baby can 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 often called "cluster feeding." Formula-fed babies may want to eat more often or will drink more formula than usual during feedings.

You'll learn to see the signs that tell you that your baby is hungry or when your baby is full. You will know your baby is hungry when she seems restless, cries a lot, sticks out her tongue or sucks on her hands and lips. You will know your baby is full when she is no longer interested in feeding or just falls asleep at the end of a feeding session. Remember, babies' tummies are very small and they need to be burped after feedings to release gas that can cause discomfort.

Your doctor will measure your baby's weight, length, and head circumference and track his or her growth on a standardized growth chart (there are different charts for boys and girls). Your baby might be large, small, or medium-sized. As long as this growth pattern stays consistent over time, chances are your baby's progress is just fine.

If your baby is born prematurely, keep in mind that growth and development should not be compared with that of a full-term child. Preemies will need to be followed more closely and may need to be weighed more often during the first months to make sure they are growing properly. They have some catching up to do!

Should I Be Concerned?

If your baby is not growing at the expected rate, or the growth rate slows, your doctor will want to make sure your baby is getting enough to eat.

The doctor may 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 frequently, perhaps every 3 to 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. At this age, bottle-fed babies may drink up to 4 to 5 ounces (118–148 milliliters) at a time.
  • How often your baby urinates. Babies should have at least 4 to 6 wet diapers a day.
  • How many bowel movements your baby has each day, and their volume and consistency. Most babies will have 1 or more bowel movements daily, but it may be normal to skip 1 or 2 days if consistency is normal. Breastfed babies' stools tend to be soft and slightly runny. The stools of formula-fed babies tend to be a little firmer, but should not be hard or formed.

Most of the time, a baby's growth will be tracked over the next few months during routine well-baby visits. But if your doctor is concerned about your baby's growth, he or she will want to see your baby more often.

What's Next?

Next month, you can expect to see your baby grow 1 to 1½ inches (2.5 to 3.8 centimeters) in length and gain about 2 pounds (907 grams).

At this rate, it may seem like your baby is outgrowing clothes every other day and you can't keep up. Don't worry. Rapid growth will slow down in the second half of the first year.

Reviewed by: Cristy A. Wong, MD
Date reviewed: January 2019