As new parents, one of the most surprising things to learn is how tiny and rapidly changing your newborn's stomach is. Understanding these changes can help you feel more confident in your baby's feeding journey and ensure they are getting what they need to grow healthy and strong.
Day 1: The Size of a Cherry
On the first day of life, your baby’s stomach is incredibly small—about the size of a cherry (approximately 5–7 ml or 1 teaspoon). Because of this, they can only hold a tiny amount of milk at a time.
What does this mean for feeding?
l Newborns need to feed very frequently, every 1–3 hours.
l Don’t worry if your baby seems to drink only a little. Their stomach is doing its job, and colostrum (the early milk you produce) is perfectly designed for this small capacity.
Key Tip: Colostrum is rich in nutrients and antibodies, and even small amounts are enough to nourish your baby during these early hours.
Day 2–3: The Size of a Walnut
By the second or third day, your baby’s stomach begins to grow to roughly the size of a walnut (about 22–27 ml, or 1 ounce). This rapid change explains why newborns often want to feed more frequently during this time.
What to Expect:
l Your baby may start to latch for longer periods.
l Frequent feeding stimulates your milk supply to transition from colostrum to mature milk.
Key Tip: This increased hunger is normal! Feeding on demand will support your baby’s growth and help establish a good milk supply.
Day 4–7: The Size of an Apricot
By the end of the first week, your newborn’s stomach has grown to about the size of an apricot (45–60 ml, or 1.5–2 ounces). With this increase in capacity, your baby may start feeding for slightly longer stretches, and you may notice slightly fewer feeding sessions during the day.
What does this mean for you?
l Your mature milk comes in around this time, providing a higher volume and more calories.
l Your baby is better able to tolerate larger feeds, which will help them stay full a little longer.
Key Tip: Continue to monitor your baby’s hunger cues (e.g., rooting, sucking on hands) and feed on demand.
Week 2–4: The Size of a Large Egg
By the end of the first month, your baby’s stomach grows to approximately the size of a large egg (80–150 ml, or 2.5–5 ounces). With this growth, feedings may become more predictable, and you’ll notice a rhythm forming around feeding times.
What to Expect:
l Your baby might start spacing feeds 2–3 hours apart.
l They’ll be more alert and engaged during feedings.
Key Tip: A consistent feeding schedule will emerge over time, but it’s normal for babies to cluster feed (feed more often) during growth spurts.
Understanding the rapid changes in your newborn’s stomach size helps set realistic expectations about feeding. It reassures you that frequent, small feedings are perfectly normal in the first days and weeks. Remember, your baby is growing quickly, and their nutritional needs are constantly changing.
Final Tips for New Parents
Trust Your Baby: Hunger cues like rooting, crying, and sucking on hands are the best indicators that it’s feeding time.
Trust Your Body: Your milk supply adjusts naturally to meet your baby’s needs. The more your baby feeds, the more milk your body produces.
Patience and Rest: Frequent feeding is demanding, but it’s temporary. Support from loved ones can make this period easier.
As your newborn grows, so will their appetite and stomach size. By understanding this journey, you can approach feeding with confidence and peace of mind. Remember: every baby is unique, and your pediatrician is there to help if you have questions or concerns.
Happy parenting!
References：
La Leche League Canada, (2022), Newborns Have Small Stomachs
https://www.lllc.ca/newborns-have-small-stomachs
UNChealthcare, (April 10, 2020), How a Baby’s Digestive System Works, for Parents
https://healthtalk.unchealthcare.org/how-a-babys-digestive-system-works-for-parents/
