Eli5: When a baby is in the womb, where does the waste go?


Eli5: When a baby is in the womb, where does the waste go?

In: Biology

I *think* that there is no waste. Could be wrong, but I’m pretty sure that they aren’t digesting food, they are just absorbing the nutrients straight from the mother. The mother eats, and does all the hard work of chewing, digesting, and separating the nutrients from the waste, and then just straight up gives the ready prepared nutrients to the baby. Theres no waste in what the baby gets.

They pee and then drink the pee—it’s a large component of the amniotic fluid. Most of the poop just goes back into mom but a little bit stick around to become the first poop called meconium

Since they’re not eating there isn’t really poop, at least not how we normally think of poop. Instead of poop, the baby makes something called meconium, which is kind of like poop but made up of water, skin cells, little hairs that fall off the baby’s body, pee that the baby swallows, etc. Usually the baby just keeps that meconium inside until after they’re born and then the release it as if it was a poop (but it looks different than normal poop).

Pee is just released into the fluid that the baby floats in (amniotic fluid) and the baby floats in it and takes it in through their nose and mouth (it’s sterile so no big deal).

A babies digestion system does not start working before they are fed. So there is no poop while the baby is in the womb. As for the pee it is a bit different. For most of the baby’s development the kidneys will not work so there will be no pee. Instead the blood will be pumped through the umbilical cord where any waste products gets filtered into the mothers blood and out through her kidneys and urine. Even after the kidneys of the baby starts working this system will filter out most of the waste from the baby’s blood. And the little urine there is will be absorbed by the walls of the womb.