When an unborn baby poops, where does it go? I know the mother excretes the fetus’ excretions–I’m just wondering if it all goes into her urine, solid-ish matter included.
How does a baby get oxygen? The umbilical cord provides nutrients–does it provide oxygen as well? Essentially: how is the blood oxygenated in an unborn baby, as his/her lungs are not extracting it from the air?
Justr a-wonderin’.
A fetus doesn’t eat, so I don’t think it poops. It gets oxygen and nutrients from the mother through the umbilical cord.
I am not a doctor.
First, no, I’m not a doctor. But I am a mother of three children, so I know a little about the subject at hand.
First, babies get rid of waste products through the umbilical cord until they’re ready to be born. Yes, Mom becomes a waste disposal system.
Some babies, however, have this tendency to be born late. Like my first daughter. When babies are overdue, one of the problems that can occur is that they will get rid of this waste in the same way we do. Not good. If the baby aspirates this, it can cause some serious problems, infections, pneumonia, death. So doctors don’t like mothers to go too far over their due dates.
Second, babies get their oxygen through the umbilical cord. Lots of give and take in that tube. Good thing it’s through separate tracks, hunh? Red track, oxygenated blood and nutrients. Blue track, waste material and oxygen depleted blood.
Feel free to shoot holes in these comments if you find I’m wrong. I didn’t get a good look while all this was taking place with my kids. Wrong angle, I guess. 
As explained previously, babies get oxygenated blood from their mothers through the umbilical cord. The fetus’s circulatory system is a little different though. There’s no point in sending the blood through the baby’s lungs to pick up oxygen so the left and right halves of the heart are not isolated. There is a hole in the septum between the ventricles allowing the blood from both halves of the circulatory system to mix. The hole narrows as birth nears, but infants are born with an imperfect septum. It’s no big deal usually, unless for some reason it is larger than average or doesn’t go away. If it persists or becomes a problem it’s referred to as a ventral septal defect (VSD). Babies with a VSD are sometimes called “blue babies” since their poorly oxygenated blood gives them a purplish-bluish tint.
Sometimes the foetus does deficate into the within the membrane of amniotic fluid, causing the fluid to become clouded and slightly green. Foetus faeces is called meconium, it is usually green/brown in colour, and it’s what the new-born baby shits for the first couple of days after delivery.
It was my orginal guess that the oxygen came from the umbilical cord, but what I don’t understand is how that works when mother and child have different blood types and/or Rh factors. In addition, I don’t understand how an HIV positive mother could have a child that is not infected with the disease if blood is so readily shared , yet that is sometimes the case. What preventive factors are there?
(I did see Cecil’s recent column about RH factors affecting the pregnancy, so I’m aware of those effects–I’m just curious how different blood types can be shared without ill effect to either.)
To expand on what DvousMeans said, the fetus doesn’t routinely excrete into the amniotic fluid–there’s an anal plug that blocks the rectum, for one thing. The first couple of days after birth, this is what the newborn baby poops. During labor and delivery, however, sometimes the baby is under stress, and it poops a little bit into the amniotic fluid. 90% of the time this is the signal for an immediate C-section, depending on what else is going on with the mother and the baby.
Sharing blood between mother and baby IS sometimes a problem. The Rh factor means (as I had it explained to me) that the mother is producing antibodies against her own fetus, which if not dealt with will cross the placenta through the umbilical cord and eventually kill the baby. So, if you’re pregnant, and your doctor determines that Rh may be a problem, right after your baby is born you get a shot of Rh globulin, which basically UN-immunizes you against any future fetuses. If the mother’s body has one kind of Rh factor, and the fetus has the opposite kind, that’s when the trouble starts. The shot is to calm all that down for the benefit of subsequent pregnancies.
Sorry if I’ve got some of the tech stuff wrong. It was all a long time ago.
Rh problems arise when the baby is Rh positive and the mother is Rh negative. Seeing the baby as foreign, the mother could produce antibodies against the baby. This usually isn’t a problem with the first pregnancy, but it sensitizes the mother’s system to react quicker to the 2nd Rh positive baby.
The blood type isn’t a problem since the red blood cells (which is what the blood type describes) don’t cross from mother to baby. Their blood circulates in the placenta in separate networks of vessels, exchanging O[sub]2[/sub] and nutrients through diffusion.
As to baby waste, they do pee. That’s what constitutes the amniotic fluid. But since most of their waste is sent out via the umbilical cord, it isn’t harmful.
Just a bit of a nit to pick: DDG is correct that meconium in the amniotic fluid is a possible sign of stress, but it does not necessarily or even usually require a C-section. A section may be indicated if there are other signs of disress, but if it is just meconium, it merely means that the baby will be more vigorously suctioned at birth and a neonatologist will most likely be called in to look the child over just in case.
I have 4 children, all of whom pooped in their bath water, so to speak. 11 years ago, the presence of meconium was enough to send me out of the LDR and into the “fetus frightening room”, but during subsequent births it merely meant that my husband didn’t get to cut the cord and I had to wait a few minutes before I could hold the baby.
OK. It looks like I was wrong. A fetus can (though usually doesn’t) poop. I think of poop as what is left over after the body has extracted everything it wants. What is there for a fetus to process. Amniotic fluid? Or is the poop just the digestive juices? Does it contain E. Coli? (Where does E. Coli come from anyway?)
One of the components in feces is breakdown products from worn out red blood cells (bilirubin, IIRC), so that may be one component of meconium.
An interesting thing I learned (while reading up on pregnancy while our kids were on the way) is that, while the maternal and fetal blood supplies are normally isolated from one another (Rh disease and HIV transmission are caused by very small leaks), the maternal blood supply in the placenta is actually an open pool in which the placental capillaries are bathed (note that the placenta is part of the fetus, not the mother). The placenta produces a substance that causes the capillaries in the uterine wall to essentially dissolve, thus creating a nice, rich blood bath for nourishing the fetus :). The pool of blood is sealed in at the placental margins. All the open blood vessels in the uterus seal off as the uterus shrinks immediately after birth. This is why the professionals (be they doctors or midwives) are very concerned that the placenta be fully delivered immediately, and that the uterus makes rapid progress in shrinking right after delivery (my wife hated the damn nurses coming in every hour to “massage” her uterus). If these things don’t happen, major hemhorraging can result.
You may resume eating your lunches now.
Rick
I do not have anything to add really to the discussion as pretty much everything has been covered.
The oxygen is passed from Mom to baby via the Umbilical cord and the blood is not swapped unless there is a problem.
The baby does exist in its urine (the amniotic fluid). It generally does not poop until after it is born. For the rest mom does handle the removal of wastes and such.
I marvel at this entire process. It is just utterly amazing to me.
On our second child (the one born 14 weeks premature), the placenta was detatching from the wall of the uterus. The baby was getting oxygen, though they were not sure for how much longer. She was getting nutrients, though again they were not sure how much longer. She was peeing, but it was not staying in the sack. So they were not sure what the problem was until after our daughter was born. In fact, even after analysis of the placenta, the doctors are still not sure what caused it. The processes mentioned are very important to the development of a baby, believe me I now know.
Jeffery