How Does a Baby’s Stomach Grow to Accommodate More Milk?

“Not only are newborn stomachs small, but they don’t expand like adult stomachs, especially in the first day. A 2001 study found that during the first 24 hours of life, a newborn’s stomach doesn’t yet stretch the way it will later. The walls of the newborn stomach stay firm, expelling extra milk rather than stretching out to hold it (emphasis mine.)

By 3 days of age, as the baby takes more and more of these small, frequent feedings, her stomach can expand to about the size of a ping-pong ball to hold more milk (Zangen et al. 2001.)

The following gives you a sense of how a baby’s feedings increase in amount over the first month.

Baby’s Age/Average oz. (ml)per feeding:

3 days/1 oz. (30 ml)

1 week/1.5 oz (45 ml)

2 weeks/2-2.5 oz (60-75 ml)

1 month/3-4 oz (90-120 ml)

Would it be beneficial for you to give your newborn more milk at each feeding and try to stretch out his stomach sooner? No, this is not a case of ‘more is better.’ Why not?

For one thing, small, frequent feedings set up a healthy eating pattern right from the start. Just as nutritionists are now advising adults to eat smaller, more frequent meals, the same goes for babies and children.

However, many new parents are encouraged to try to give their babies as much as possible at each feeding and feed fewer times per day, which can lead to overfeeding.”

From Breastfeeding Made Simple, by Mohrbacher and Kendall-Tackett, 2010.

Next post: The importance of small feedings for the newborn.