Why and How Do Babies Move in the Womb?

[Imparcticle]

My sister is pregnant (and is married) and of course, her baby has been moving around. She was wondering why and how this happens. In addition, she was told by a co-worker that babies (while in the womb) have hiccups. Is that true?

 

[recon]

Hmm... I also have a question to ask about babies. I saw on TV that babies are natural swimmers and that this ability disappears after a while. Can this ability of theirs be attributed to the fact that they have spent so much time in their mother's womb?

 

[Moonbear]

I don't know about them being natural swimmers...they float because of all the fat, but they sure don't know to lift their head out of the water.

Yep, they do get hiccups...and your sister will definitely know it when it happens! Even after they are born, they have a lot of involuntary movements, probably as the nervous system develops and triggers muscle contractions, etc. I don't know why they move around, other than that it is important at the end of the pregnancy that the baby turn so they are in the right position to be born, the rest is probably somewhat random while they still have lots of room to float around so any movement sends them zipping in a new direction :-)

Sorry I can't be of much more help there...it's funny, my research is in reproduction, but my expertise quickly dwindles once someone has accomplished pregnancy...I know much more about what happens for someone to get pregnant.

 

[Monique]

Babies are not natural swimmers, but they have a reflex that causes them to hold their breath when underwater. An older baby would panic and try to breathe.

 

[Moonbear]

Makes sense that Monique would know this...surrounded by water the way she is! Though, that leaves the question of how or why that reflex developed. Fetuses don't "hold their breath" in the womb, they breathe in amniotic fluid all the time. Makes you wonder if there's some aquatic species in human ancestry that such a reflex would exist so consistently, or do a lot of people slip with newborns in the bathtub? They do get slippery!

 

[Imparcticle]

Don't unborn babies have pharangeal gills? That's how they breathe, I believe.

 

[wasteofo2]

Don't unborn babies have pharangeal gills? That's how they breathe, I believe.

I thought they had some sort of gils very early in development, but they soon disappeared (like their tail), and that oxygen was passed from mother to baby through the blood passing through the umbillical cord.

Of course, I could be totally wrong.

 

[Monique]

Don't unborn babies have pharangeal gills? That's how they breathe, I believe.

I've never heard a credible account on these gills, apparently they appear very early in development and quickly disappear. Oxygen is transferred from the mother's blood to the child's blood in the placenta through a barrier so that there is no blood contact.

 

[russ_watters]

...and if they "breathed" amniotic fluid (yeah, I saw "The Abyss" too...), then when they are born they'd quickly drown. In actuality, they have a blockage in their throat which is cleared so they can start breathing

 

[Imparcticle]

I've never heard a credible account on these gills, apparently they appear very early in development and quickly disappear. Oxygen is transferred from the mother's blood to the child's blood in the placenta through a barrier so that there is no blood contact.

Wow, that's intriguing. I hope you don't mind if I bombard you with questions:

1.)How do placenta selectively permeate oxygen?

2.)What kind of structure do placenta take on?
3.)How are they different from regular cells?
4.)Where do they come from?
5.)Do they only occur in pregnancy?
-------If not,
--------------then where and when do they occur?
--------------How different are they from those placenta found in pregnancy? (i.e., if there are placenta in an adult, how different are they from developing babies?)
--------------What purpose do they serve in adults?
--------------Where else can they be found?


------If so,
-------Why?
-------Why only in pregnancy?
--------------how early in pregnancy do they occur?
-------Do they have mutliple roles besides only permeating (sp?) oxygen?


6.) How are they related to the cell membrane?
7.)Are placenta only found in humans? Why or why not?
8.) Are they susceptible to the Rh factor?
9.) Do they carry DNA?
-------If so,
Who's? (the mom's? the dad's? the babies?)

--------If not,
Is it possible for them to carry RNA? (i'm guessing no?)
How are they made?? Red cells don't have DNA either. I never understood how it is they take on their structure and function without DNA. Just how do they do it?

Thank you in advance.

 

[chroot]

All people (not just newborns) have a reflex that helps prevent drowning: laryngospasm.

http://en.wikipedia.org/wiki/Drowning

- Warren

 

[Imparcticle]

how does that work, chroot?

 

[chroot]

Did you... read the link?

Upon water entering the airways, conscious or unconscious victims show laryngospasm, i.e. the Larynx or the vocal cords in the throat constrict and seal the air tube. This prevents water from entering the lungs. Due to this laryngospasm, water enters the stomach in the initial phase of drowning and only very little water enters the lungs.

- Warren

 

[Monique]

Imparticle, I'm not sure what you are asking about.. but the placenta is a structure made by the fetus, which is in contact with bloodvessels from the mother. It is in that plane where exchange occurs of nutrients. The blood of the fetus and the mother never is in direct contact, there are a layer of cell through which the molecules have to diffuse. So if a mother has HIV, the child won't catch it. The mother also won't have a problem when the baby is of a different bloodtype (rhesus factor CAN become a factor, since small antibodies are able to pass the barrier).

About your question on red blood cells, they loose their DNA along the way of differentiation.. they only function as oxygen transporters and don't divide further so don't need the bulky nucleus.

 

[Imparcticle]

How do babies get HIV?

sorry chroot, didn't see. (i'm in a hurry)

 

[iansmith]

So if a mother has HIV, the child won't catch it.

Are you sure about that? HIV particle is small enough to pass through the cell barrier of the umbilical cord.

7.)Are placenta only found in humans? Why or why not?

No there such a thing call placental mammal


Here some link about placenta development. http://www.geocities.com/cmorales4/p58.html
http://www.lrsd.ab.ca/staff/brownr/science/bio30/gestation.PDF
http://www.google.ca/search?q=cache:oimNXRia2X8J:studentmidwives.co.uk/pages/essays/001/Formation%2520of%2520the%2520placenta%2520and%2520the%2520third%2520stage%2520oflabour.doc+placenta+formation&hl=en

 

[Monique]

Are you sure about that? HIV particle is small enough to pass through the cell barrier of the umbilical cord.

You're right:

About 25 to 33 percent of all pregnant women who don't take the drug zidovudine (AZT) during pregnancy will pass HIV to their babies. Taking AZT while pregnant and having a cesarean, or C-section, delivery drops a woman's chances of passing HIV to her baby to 1 percent.

85-95% of infants contract Hepatitis B while being born, and the remainder through transplacental transfer or while breastfeeding.

Apparently the transfer of Hepatitis C from mother to her unborn child is 7%.