Growth and Development

Your Baby's Growth: 3 Months

Most babies continue to grow in weight and length this month.

How Much Will My Baby Grow?

The first few months of life are a period of rapid growth. Your baby will gain about 1 to 1½ inches (2.5 to 3.8 centimeters) in length and 1½ to 2 pounds (681 to 907 grams) this month. These are just averages — your baby may grow somewhat faster or slower, and is likely to have growth spurts.

If your baby is extra fussy or wants to eat more than usual, it's probably due to a growth spurt. If you breastfeed, your baby might want to eat more often (what may seem like every hour!), especially at certain times of the day. Some people call this "cluster feeding." Formula-fed babies may want to eat more frequently or will drink more during feedings.

Pay attention to signals that your baby is hungry (sticking out the tongue or sucking) or full (turning away or dozing off). If the fussiness continues for more than a day or two, talk to your doctor.

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). Whether your baby is large, small, or medium-sized, as long as this growth pattern stays consistent over time, chances are everything is 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 3 months old, a breastfed baby may feed 8 times in a 24-hour day; formula-fed babies usually eat less frequently, about every 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 eat up to 6 to 7 ounces (177 to 207 milliliters) at each feeding.
  • 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 should 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 simply 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?

Your baby will continue to grow in length and weight at a steady rate. By 4 months, most babies have doubled their birth weight.

Reviewed by: Mary L. Gavin, MD
Date reviewed: December 2014

Kids Health

Note: All information is for educational purposes only. For specific medical advice, diagnoses and treatment, consult your doctor.

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