# do we know what causes dilation?



## readytobedone (Apr 6, 2007)

my doctor seems to think it's the baby's head applied to the cervix (when i told him my mom never dropped with her first and went 2 weeks "late," he told me "of course" she went 2 weeks late because "there was nothing to dilate her cervix"), but by that standard, no one could dilate unless baby was head-down and pretty much engaged, right?

and obviously people do...i read birth stories about women who get pretty dilated but then have to push baby down because he or she is still high.

even my birth instructor said you "can't dilate past 5" without the cooperation of the baby's position (meaning well-applied to the cervix), but then how to women deliver vaginal breeches?

it doesn't add up to me...


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## alegna (Jan 14, 2003)

They don't know. There are a lot of factors- pressure being one of course. But it comes down to, like so many things about labor and birth, it's a complicated dance of physics, hormones and who knows what else that we don't understand the tip of.

-Angela


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## readytobedone (Apr 6, 2007)

Quote:


Originally Posted by *alegna* 
They don't know. There are a lot of factors- pressure being one of course. But it comes down to, like so many things about labor and birth, it's a complicated dance of physics, hormones and who knows what else that we don't understand the tip of.

-Angela

thanks, this is kind of what i figured, but as you well know, docs don't like to say they don't know things


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## alegna (Jan 14, 2003)

Quote:


Originally Posted by *readytobedone* 
thanks, this is kind of what i figured, but as you well know, docs don't like to say they don't know things









Yet another reason I avoid them whenever possible









-Angela


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## pamamidwife (May 7, 2003)

there are a couple different factors:

with every contraction, the top of the uterus puhes the baby's presenting part down. This helps to open the cervix. the lower part of the uterus pulls up - kind of like when you pull a turtleneck over your head. the lower part of the uterus gets thinner as labor advances, the upper part (the fundus) gets thicker as it follows the baby down.










even if baby was high or a shoulder was presenting, the uterus can still help the cervix dilate. sometimes without a presenting part or evenly presenting the cervix can dilate slower or more uneven. however, this is not always the case.

the uterus is powerful and strong!


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## Vespertina (Sep 30, 2006)

I asked the same thing both times and I never really got an answer. With my second, my water was broken at 6 cm to induce labor, she was at -2 station. I was 7 cm before labor started with my second, head at -1.

Same with my first. I got to 6.5 cm before labor contractions, her head was at -1 station.

My midwives have just said my cervix dilates with extreme ease, without significant or noticeable contractions.


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## georgia (Jan 12, 2003)

What many OBs say doesn't "add up." I'm not knocking...just pointing out that they are one of the only specialists who a great number seem to operate on personally biased opinion and myth rather than evidence-based research. (Not that giving birth requires research or a physician, IMO, but ya get my point







)


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## AuntG (Apr 2, 2007)

I'm a little confused because it always seemed pretty obvious to me that uterine contractions caused the cervix to dilate. Wouldn't be much point in having them if they didn't open up the pathway, right?


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