Your baby’s digestive system is well under development by the time they make their grand entrance into the world. From the very first digestive cells in the womb (the endoderm) to the very first poop (meconium), the baby’s digestive system development process will continue over the first year of life.
Transitioning from womb to the real world
When babies are safe and snug in the womb, they receive the nutrients they need and dispose of waste through the placenta. After they are born, this all changes for your little one.
It takes time for baby’s digestive system to rev up and adjust, which is why it is not uncommon for your little one to lose up to 10% of body weight during the first few days of life. Breast milk, being high in fat, is the most efficient way for babies to get the calories they need to pack on the pounds. Keep in mind, however, that it will take a week or so for your breast milk to transition from colostrum (the “first milk” which contains loads of nutrients and antibodies for your baby) to fat-dense milk, which may contribute to your baby’s initial weight loss.
Frequent feedings and spit ups are normal
Your baby’s tummy is quite small, which is why they will need to be frequently fed during the first few months of life. On the baby’s first day they can hold less than one ounce of food. By three months, this will increase to approximately four to five ounces.
A baby’s oesophageal valve (which controls the entry of food in your baby’s stomach) is also underdeveloped. This causes them to spit up frequently during the first three months of life.
This, in combination with babies’ immature kidneys, is why it is important to feed them regularly to prevent dehydration, electrolyte imbalance, and to ensure that they are getting the nutrients they need to be healthy and strong.
A digestive lining in the making
The gastrointestinal tract of healthy older children and adults has a layer of mucus which protects our bodies from contaminants and microbes present in the foods and liquids we consume. Infants, having an immature protective layer, are at a greater risk of infection as a result.
Your baby’s digestive lining will not mature until they are around six months old at which point they will also start producing their own antibodies. Until that time, the antibodies in your breast milk will go a long way in protecting your baby. Your breast milk also contains intestinal growth factors that will help baby develop colonies of good gut bacteria that will promote the maturation of that lining while protecting them from dangerous pathogens.
Expect lots of wet nappies
Your newborn may only have one wet nappy and one tarry black meconium stool on day one. From then on stools will increase in frequency and transition from blackish to greenish, brownish or yellowish, and they will eventually have anywhere from eight to twelve wet nappies for the first three months of life.
A word about solid foods
Newborns can digest fats, proteins and carbohydrates. But because the pancreas is immature, babies produce substantially lower levels of digestive enzymes than older children and adults.
Your baby gets some much-needed help in the digestive enzyme department from two things:
- Your breast milk
Babies may exhibit an interest in solid foods as young as two months old, but don’t hand them a piece of mushy banana just yet. Between the age of four to six months, they will have what is called an “open gut” which can allow for large solid food molecules to pass through and can cause allergies or infections.
Your baby’s digestive system development will not have reached sufficient levels of enzymes to process the complex starches and carbohydrates in our foods until they are between six and nine months old, at which point you can begin to introduce solid foods gradually.