When welcoming your newborn into the world, every parent faces a steep learning curve, particularly when it comes to understanding your baby’s sleep and feeding habits.

One of the key factors that play a crucial role in both of these areas is the size of your baby’s stomach. In your baby’s first few weeks of life, their stomach goes through rapid changes in size, which impacts how frequently they eat and how well they sleep.

Keeping this in mind, let’s explore how a newborn’s stomach influences their digestion and sleep patterns. By understanding this connection, you can better navigate your baby’s feeding and sleep schedules, and ensure their comfort during this important stage of development.

Whether you’re a new parent or looking to refresh your knowledge, this guide will provide important insights to help support your baby’s growth and health. 

Understanding newborn stomach size

Before we delve into the size of your baby’s stomach, it’s important to note that there is a difference between what your baby’s stomach should hold vs what it can hold.

When we say size, we mean the volume of milk a baby can comfortably consume. If you feed your baby formula, they may be able to take even more. Furthermore, there is no one-size-fits-all in baby stomachs. 

Just like your baby might be a different size or weight as compared to another baby, so it is for their stomach. Additionally, your baby’s ability to breastfeed or drink, and the speed at which digestion occurs, also play a part.

The size comparisons described below are guidelines on how much milk a baby can be expected to drink. Their stomach may not grow day to day or be that size.

Day 1: Your baby’s tummy is the size of a marble or pea

At this early stage, your baby can only consume roughly one tablespoon, which is why you’ll probably only price a limited quantity of colostrum (the first form of milk produced immediately following birth) during each feed.

Day 3: Your baby’s tummy is the size of a walnut

Come day three, your baby’s stomach will have grown to the size of a walnut, able to hold 0.5 to one ounce of liquid. At this stage, your breast will be fuller and begin producing transitional milk which is whiter and more fluid.

 Day 10: Your baby’s tummy is the of a golf ball

By day 10, your baby should be able to take 1.5 to two ounces of liquid per feed and should be closing in on their birth weight if feeding is going well.

The chart below gives an estimate of how much fluid your baby will be able to take as they grow:

The Digestion process in newborns and sleep patterns

The digestion and absorption of food are closely related to growth and long-term health in infants. It takes your baby’s stomach an average of 48 minutes to half-empty when given breast milk. For formula-fed babies, this extends to 78 minutes.

It is important to note that at birth, your baby’s digestive system has not yet fully developed and cannot break down food perfectly. This can sometimes cause mild digestive problems.

As your baby’s body digests food fairly quickly (for a newborn), and their stomach is so small, it is understandable that they wake frequently to eat. They require multiple small feedings for proper nutrient absorption. While newborns can sleep between 11 to 17 hours in 24 hours, your baby will wake every 30 minutes to three hours to feed.

Most babies don’t begin sleeping through the night (five to eight hours) until six months to one year of age and this varies from baby to baby. Now, how often your baby will wake to feed depends on what you feed them and their age. If you feel your baby is sleeping too much and not waking from hunger, speak to your doctor to see if you should wake your baby to eat.

The American Academy of Pediatrics recommends you feed your baby on demand when they show signs of hunger such as sucking on their hands or rooting (moving their head “in search” from side to side). You’d feed your baby roughly eight to 12 times every 24 hours. As your baby and their stomach grow, these feeding sessions will reduce.

Conclusion

As your baby’s stomach grows, so will their feeding and sleeping capabilities. Understanding the relationship between your little one’s stomach size, digestion, and sleep patterns can help you better manage their feeding routine and sleep schedule and ultimately create a peaceful environment for you and your baby.

It’s important to recognize your baby’s individual cues for food and sleep so you can adjust your routine when necessary. Remember, if you’re unsure, it’s always best to consult with your pediatrician to ease your doubts or concerns.

Sources:

1. Gastric emptying of human milk or formula. National Library of Medicine. Gastric emptying in infants fed human milk or infant formula.
2. Stomach capacity in newborns. Alabama Public Health. Stomach Capacity.
3. Development of a newborn’s digestive system. National Library of Medicine. Development of the digestive system in early infancy and nutritional management of digestive problems in breastfed and formula-fed infants.
4. Protein digestion in babies. National Library of Medicine. Protein digestion of baby foods: study approaches and implications for infant health.
5. Infant digestion. Synergea Family Health Centre. Infant Digestion.
6. Sleep patterns in newborns. Johns Hopkins Medicine. Newborn Sleep Patterns.
7. Newborn stomach size. 2018. ScienceNews. No matter their size, newborn stomachs need frequent filling.
8. AAP breastfeeding recommendations. American Academy of Pediatrics. Breastfeeding: AAP Policy Explained.