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A Step-by-Step Guide to Your Baby’s Digestive System Development

Growing a tiny person inside of you is a joyous and remarkable process. Every part of your baby’s body, from bones and muscles to complex organs, must form in stages in order to develop correctly.

Let’s take a look at how your baby’s digestive system develops in the womb, and then what kind of excretions you expect to see once he/she arrives in the world.

First trimester: building blocks of baby’s stomach

3 weeks: Your baby is an embryo with three layers of cells. The inner cell is called the endoderm, and it will grow and morph and become your baby’s digestive system.

8 weeks: A tube that will become the digestive tract starts forming. It’s too large to fit inside your baby, so it grows into the umbilical cord. Your baby also has their first set of tiny temporary kidneys to help remove waste from their body.

10 weeks: Your baby has a stomach and their final set of permanent kidneys! You baby is getting their nutrition from you, and producing digestive enzymes and urine.

Second trimester: getting up to speed with digestion

13 weeks: Your baby’s digestive system is now fully formed, and nestled into position within its body. Your baby starts swallowing amniotic fluid, training their muscles and organs to contract and pass the fluid through. Your baby pees every 40 minutes.

Your baby also has taste buds on their tiny tongue. The flavours of the foods you’re eating come through in the amniotic fluid, so your baby’s taste influences your food cravings.

Third trimester: ready for launch

Final weeks: Your baby continues to practice and perfect digestion as they grow and form. Your baby’s first bowel movement starts to build up in their intestine. This isn’t food, but old blood and skin cells collected in their intestines.

Happy birthday! Welcome to the world! On their first day in the world, you’ll notice your baby’s first bowel movement. Sometimes, your baby might do this while still in utero. That means your baby might breathe in amniotic fluid that could irritate or damage their tiny lungs. If you notice green or brownish amniotic fluid, let your midwife know.

Newborn baby: All the poop of the rainbow

In the first few weeks of your baby’s life, you’ll discover a whole new world of poop colours you never knew existed. As a newborn, your baby’s poop will be brown/black, and sticky. Once they start feeding, their poop will range in colour from green, yellow, orange and brown.

Key things to watch for are red or black stool – signs your baby may have internal bleeding – and white poop – indicating your baby isn’t properly absorbing certain nutrients. Runny poop or poop containing mucus might indicate an infection, and hard, pebble-like poop may be a sign your baby is constipated. If you notice either of these things, contact your doctor immediately.

Of course, you’re going to need something to clean up all this poop, and make sure baby’s bottom is clean and dry to prevent nappy rash.


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