Baby’s Digestive System – When and How it Develops?

Baby’s Digestive System – When and How It Develops?

Medically Reviewed By
Dr. Gunjan Baweja (Paediatrician)
View more Paediatrician Our Panel of Experts

Babies are delicate and so is their digestive tract. Whatever your baby puts in his mouth may enter his gastrointestinal tract, which is not strong enough to fight various kinds of pathogens or bacteria that enter his body. In the initial months of your baby’s life, his digestive tract will undergo many changes. For the first few months, it will not only produce various enzymes that help and aid digestion, but it will also develop antibodies to fight various infections and medical ailments. To know when and how a baby’s digestive system develops, read the following article.

An Infant’s Digestive System Transition From Womb to Birth

The transition from the womb to birth marks a crucial phase in an infant’s development, particularly in the adaptation of the newborn digestive system to the newfound independence from the placenta. This process involves significant changes as the infant’s body prepares to digest food independently. Below, we explore the different stages of an infant’s digestive system, both in full-term and preterm births.

1. Fetal Digestive System in the Womb

During the gestation period, the fetal digestive system relies on the placenta for the supply of essential nutrients. The placenta acts as a bridge between the mother and the developing baby, providing the required sustenance for growth. This phase plays a vital role in the initial formation and preparation of the digestive organs, setting the foundation for the digestive processes that will follow after birth (1).

2. Infant Digestive System (Full-Term Birth)

Upon birth, the infant’s digestive system undergoes a significant shift as it transitions from being dependent on the placenta to functioning autonomously. The immature and delicate nature of the digestive organs at this stage requires time for adjustment (2). In the early days, infants may experience a weight loss of around 10%, reflecting the initial challenges faced by their digestive systems (3). Breast milk emerges as a crucial component, providing the necessary nutrition and energy for the baby’s growth and development. The transition from colostrum to nutrient-rich milk is a key milestone, contributing to noticeable weight gain as the infant’s digestive system strengthens (4).

The infant’s smaller stomach capacity necessitates frequent feeding, starting with small amounts and gradually increasing as the digestive system matures. Challenges such as a small and underdeveloped esophageal valve may lead to frequent spitting. Additionally, the immature kidneys emphasize the importance of a carefully monitored feeding schedule to ensure proper nutrient intake, hydration, and electrolyte balance.

3. Infant Digestive System (Preterm Birth)

In the case of preterm births, where infants enter the world before completing the full term of gestation, the digestive system faces additional challenges. Premature infants may have underdeveloped organs, including the digestive tract, requiring specialized care and nutritional support (5). Feeding strategies for preterm infants must be adapted to accommodate their unique needs, taking into account the delicate state of their digestive systems. Close monitoring and adjustments to the feeding schedule become crucial to support their growth and development in a manner that aligns with their preterm status.

The Digestive Tract Lining Issue

Adults and older children have a layer of mucus lining around their gastrointestinal tract. This mucus lining acts as a shield in protecting the digestive tract against any microbes or contaminants that they may consume with their food or liquids. However, babies do not have a strong mucus lining around their gastrointestinal tract. This may put babies at high risk of catching various kinds of infections. However, this should not be your cause of concern because as your baby will grow, this lining will become stronger and will mature completely and your baby’s body will become strong enough to start making its own antibodies. Before your baby’s body starts making its own antibodies, your baby will get them from the breast milk. Apart from this, the breast milk will also help your baby in building the mucus lining by promoting the good bacteria and keeping various dangerous pathogens at bay.

The Digestive Tract Lining Issue

Why Avoid Solid Foods Until 6 Months?

You may be tempted to give a morsel of food to your baby when you have your meals. However, if your baby is less than six months of age, this may not be a good idea. This is because no matter how eager or ready your baby may be, his digestive system may not be ready or prepared for the same (6). Your baby’s body will not be efficient enough to produce the apt amount of enzymes to digest starch in the food until he reaches six months of age. Also, bile salts and lipase, which aid in the digestion of fats, do not reach a maturing stage until six to nine months of age. By four to six months of age, your baby will have an ‘open gut’. This gut will allow the whole proteins to pass from the small intestine to the bloodstream. This will also aid the antibodies from the mother’s milk to enter into the bloodstream; however, if large molecules of food or other pathogens pass through it, it may lead to allergies or infections.

When Does a Baby’s Digestive System Develop Fully?

Are you thinking how long it will take for your baby’s digestive system to mature? Well, your baby’s digestive system needs to make enough digestive enzymes that can help digest carbohydrates, fats and proteins present in the solid food. And this may not happen until six to nine months of age. Therefore, your baby’s digestive system gradually starts maturing at around six to nine months of age. By this time you can start introducing various kinds of solid food in your baby’s diet after checking with your doctor.

Tips to Care for Your Child’s Digestive Health

Colic, diarrhoea, spitting up, tummy pain, and other digestive problems are very common during the first few months after the birth of your child. But there is no need to worry as these are very common issues that most babies may face due to an immature digestive system. However, here we have some tips that may help you to take care of your baby’s digestive health.

1. Breastfeed

Breast milk is a boon for babies as it not only provides them with ample amount of nutrition, but it also helps in building antibodies. Therefore, you must breastfeed your baby until six months of age or longer. It has also been proved that babies who are exclusively breastfed are less likely to have digestive, respiratory, or other health complications.

Mother breastfeeding baby

2. Introduce Solid Foods Gradually

You may give solid foods to your baby once he turns six months. However, refrain from adding too many foods at the same time. Begin by slowly introducing one food at a time and the new food should be added after a gap of four to five days. Monitor how your baby’s digestive system responds to it. Bananas, broccoli, apples and cereals like rice, ragi and suji are some of the food items that you may begin with. The addition of wheat should be delayed and it can be started around eight months or after.

3. Look Out for Food Allergies

Make sure you register any allergies or food sensitivities that your baby may have as it may impact his digestive health. For this reason, it is important to start with one food item at a time to know if a particular food item may be the culprit behind the food allergy. If your baby is allergic to any food item, make sure you refrain from giving any food preparation that may contain that food item in it. Some babies may be lactose intolerant, may have nut allergies or even be allergic to eggs. So, keep a good eye on your little baby.

4. Ensure Proper Hydration

Adequate hydration is crucial for maintaining a healthy digestive system in children. Water plays a key role in digestion and helps prevent constipation. As you introduce solid foods, gradually incorporate water into your child’s routine. Ensure that your child drinks an appropriate amount of water throughout the day to support optimal digestion and overall well-being.

5. Encourage Physical Activity

Physical activity is beneficial for digestive health. Encourage age-appropriate activities to keep your child active, as this helps stimulate the digestive system. Whether it’s outdoor play, sports, or simple exercises, regular physical activity contributes to a healthy digestive tract and can prevent issues like constipation.


1. What Is Digestive Overload in Infants?

Digestive overload in infants occurs when their digestive system is overwhelmed by the introduction of too much food or complex nutrients, leading to difficulty in digestion. This can result in discomfort, fussiness, and potential digestive issues. It’s important to introduce foods gradually and monitor the baby’s response to avoid digestive overload.

2. How Can You Improve Your Infant’s Digestive System?

Improving your infant’s digestive system involves adopting healthy feeding practices. Breastfeeding provides essential nutrients and antibodies, aiding in digestive health. Introduce solid foods gradually, starting with one food at a time, and monitor reactions. Ensure proper hydration, encourage physical activity, and be mindful of potential food allergies. These practices contribute to the development of a strong and healthy digestive system.

3. What Is the Role of Probiotics in Supporting the Digestive System of a Healthy Baby?

Probiotics play a beneficial role in supporting the digestive system of a healthy baby by promoting the growth of beneficial bacteria in the gut. These live microorganisms help maintain a balanced gut microbiota, enhancing digestion and nutrient absorption. Probiotics can be particularly useful in situations like antibiotic use or digestive disturbances. However, it’s advisable to consult with a healthcare professional before introducing probiotics to an infant’s diet.

Now you know when your baby’s digestive system develops, so introduce solid foods to him once you are sure that his digestive tract is completely developed. Please consult your doctor before starting off with any kind of solid food for the first time as your doctor may be able to guide you better as to how you may go about feeding solid foods to your baby.


1. Gastrointestinal Tract Development; Embryology;

2. Moore. R, Townsend. S; Temporal development of the infant gut microbiome (Open Biology); Thr Royal Society Publishing;; September 2019

3. Infant with Loss of 10% Birth Weight; Stanford Medicine;–birth-weight.html?tab=proxy

4. McGrath. B, Fox. P, McSweeney. P, Kelly. A; Composition and properties of bovine colostrum: a review (Dairy Science & Technology); Springer Link;; September 2015

5. Demers-Mathieu. V, Qu. Y, Underwood. M, et al.; Premature infants have lower gastric digestion capacity for human milk proteins than term infants (Journal of Pediatric Gastroenterology and Nutrition); National Library of Medicine;; May 2019

6. Foote. K, Marriott. L; Weaning of infants; Disease in Childhood;

7. Starting Solid Foods; American Academy of Pediatrics;

Also Read:

Gas Problems in Babies
Reflux and GERD in Infants
Home Remedies to Improve Digestion in Babies & Toddlers

Previous article «
Next article »