How Does the Baby’s Digestive System Develop?

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5 min read

Apr 4, 2025

The digestive system is one of the most important systems in a baby’s body. It is responsible for using up nutrients and removing waste from the body. While digestion doesn’t fully function until after birth, the system begins forming very early in pregnancy.

In this article we have discussed the development of your baby’s digestive system in each trimester, let’s give it a read.

Development of Your Baby’s Digestive System in the Womb

1st Trimester

The formation of the digestive system begins early in pregnancy. By the end of the first month, the baby’s digestive tract starts forming as a simple tube. Here’s what happens during the next few weeks:

The esophagus, stomach, intestines, liver, and pancreas are developed from this tube.
By week 8, the intestines start growing which then extend into the umbilical cord because there isn’t enough space in the tiny abdominal cavity.
By the end of the first trimester, the intestines have started their wave-like motion which is known as peristalsis.

2nd Trimester

By the end of the first trimester, the physical development of your baby’s gut is complete. During the second trimester, it matures. Here’s what happens during the second trimester:

Around week 13, the baby starts swallowing small amounts of amniotic fluid. It helps prepare the digestive system.
The liver begins producing enzymes and bile.
By week 16, the intestines return from the umbilical cord into the abdomen.
The pancreas starts producing insulin which helps regulate blood sugar levels.

3rd Trimester

In the final months of pregnancy, the digestive system prepares for functioning outside the womb:

The baby continues swallowing larger amounts of amniotic fluid.
The intestines start absorbing water and simple sugars from the fluid.
By week 34, the digestive system is fully formed but remains immature until birth.
Baby’s gut starts making meconium. It is a thick, sticky substance made of swallowed amniotic fluid, dead cells, and digestive secretions. It is more commonly known as the baby’s first poop.

Do Babies Eat in the Womb?

Technically, babies don’t “eat” food in the womb the way they do after birth because they receive all their nutrients from the placenta. It delivers oxygen, glucose, fats, proteins, and vitamins from the mother’s bloodstream to the baby.

However, babies swallow amniotic fluid. It helps their digestive system practice the process of digestion once they are born. Some studies have suggested that babies can taste the foods mothers eat during pregnancy through the amniotic fluid and it influences a baby’s taste preferences after birth.

Do Babies Poop in the Womb?

While babies process fluids and nutrients in the womb, they don’t pass stool until after birth. Their intestines collect meconium, which consists of cells, digestive fluids, and swallowed substances. Meconium is normally passed as the baby’s first poop within the first 24–48 hours of birth.

Under some cases of fetal distress during birth, the baby may pass meconium in the womb, which is then aspirated. Meconium aspiration is a life-threatening emergency urgent medical attention is needed in such cases.

Conclusion

A baby’s digestive system undergoes incredible changes throughout pregnancy, from a simple tube in the first trimester to a fully developed but inactive system by birth.

The digestive system is one of the last systems to mature, and it continues to do so even after birth.

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