In which position does the baby lie inside the uterus?

  1. Hello everyone,

    I'm confused about this. This pic shows like this
    [​IMG]




    But I watched a video on youtube that showed another way.That video suggested a pic like this [​IMG]

    Is the top pic wrong and my final pic right!! Thanks!! :smile:
     
    Last edited: Jul 18, 2011
  2. jcsd
  3. Ryan_m_b

    Staff: Mentor

    The foetus/baby has it's head facing down but can rotate from side to side as I understand. So both pictures are correct.
     
  4. Evo

    Staff: Mentor

    Babies can be in many different positions even when entering the birth canal. They can be feet first (breech). Most babies are born face down, but my oldest was born face up (posterior) and almost drowned on the amniotic fluid, she was in intensive care for the first 24 hours and I couldn't even see her.
     
  5. That poster is only a representation of one of the more common lies in a term pregnancy.

    Pre-term they can be almost any position at all, but at term, space dictates they bring themselves into one of 18 lies with left occipitoanterior (your poster) and right occipitoanterior being most common and demonstrated in perhaps 70% of term pregnancies.
     
  6. Andy Resnick

    Andy Resnick 5,967
    Science Advisor
    Education Advisor

    Something interesting, is that the fetus will change their orientation (with respect to gravity) several specific times during development.

    http://www.ncbi.nlm.nih.gov/pubmed/7875103

    It's not clear if fetal motion/orientation is required for normal development, but it would be very interesting if it was.
     
  7. Ryan_m_b

    Staff: Mentor

    There has been work to investigate development under microgravity conditions which have shown that there is a difference
    http://www.ncbi.nlm.nih.gov/pubmed/20946105
    As well as studies showing altered gene expression in stem cells
    http://www.ncbi.nlm.nih.gov/pubmed/20528675

    Considering the sensitivity of cell behaviour to environmental conditions it would not surprise me that orientation with respect to gravity was a large factor in development.
     
  8. Gravity has a huge impact. Women carrying babies in a breech or transverse lie are often advised to go swimming as the weightlessness can often stimulate baby to finally move into a position more conductive to vaginal delivery.
     
  9. DaveC426913

    DaveC426913 16,381
    Gold Member

    True! (Wife is a doula. Has seen this happen.)
     
  10. lisab

    Staff: Mentor

    And the feeling of a fetus somersaulting in an already tight belly is outside of anything I had ever experienced :surprised.

    From direct experience, my answer to "In which position does the baby lie inside the uterus?"

    "All of them."
     
  11. Evo

    Staff: Mentor

    Yeah, you go to bed with your belly sticking out in one direction and you get up and it's in a completely different shape.
     
  12. Andy Resnick

    Andy Resnick 5,967
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    ryan_m_b's response was more along my line of thought. Clearly gravity has an impact on gross movement, but what is interesting (from my perspective) is the role of mechanosensation in organ/organism development. Bones, in particular, remodel themselves extensively in response to external body forces. The inner ear (otoliths, for example) has a lot of interaction with gravity as well. Finally, the lungs and sinus cavity develops mucus transport *out*- that is, a particular direction is selected. To me, it's striking that the (human) fetus undergoes abrupt changes in orientation around 5 weeks, 18 weeks, and 22 weeks (IIRC- I can't find a single useful reference....) that may coincide with certain embryonic developmental checkpoints.

    That said, one should be very careful about extrapolating bioreactor studies to true gravitational effects. In particular, bioreactors still have a lot of fluid shear stress impacting the cells which is difficult to separate out from reduced gravity experiments carried out on the shuttle or ISS.
     
  13. Ryan_m_b

    Staff: Mentor

    Definitely, I feel that the naming of certain bioreactors as "microgravity simulating" is a huge misnomer. I heard a while ago that squids have been sent to the ISS, I wonder if they are looking at development.
     
  14. DaveC426913

    DaveC426913 16,381
    Gold Member

    Well, with all those arms they could assemble a CO2 scrubber in about 30 seconds...
     
  15. Andy Resnick

    Andy Resnick 5,967
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    http://mad-as-a-marine-biologist.tumblr.com/post/5897432457/spacesquid

    Usually they are looking at embryo development (or single-cell issues)- here's C. elegans:

    http://www.space.com/6938-worms-space-study-microgravity.html

    Insects have flown, bacteria flown *outside* the shuttle to examine radiation-damage issues. A good story- mice were flown recently, but they all died from hypothermia on orbit- when they peed, the urine soaked into their fur rather than what normally happens. A colleague spent a year devising a urine collection system for the follow-on experiment.... not as glamorous as working on the space toilet, but there you go.
     
  16. DaveC426913

    DaveC426913 16,381
    Gold Member

    Certainly not glamorous if you get a "teeny tiny error" resulting in "Classified Materials Turbulence"... :biggrin:
     
  17. Andy Resnick

    Andy Resnick 5,967
    Science Advisor
    Education Advisor

    Once I was down at JSC and got a tour of the facility, including the space toilet trainer unit. The trainer unit has a camera that points *up*, tied into a (hopefully) closed-circuit TV channel so the astronaut can verify that they are "centered and sealed". It's a standing joke that if the crewperson is a jerk, the video will be leaked to the public.

    Naturally, of the whole tour, the space potty was the star attraction. :)
     
  18. Ryan_m_b

    Staff: Mentor

     
  19. Thanks for everyone who replied :smile:
     
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