# Do you know how many centimeters a woman has to be dilated to give birth? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [September 15, 2014, 4:20pm UTC](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573 "2014-09-15T16:20:47Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Yllaria](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yllaria/32/3452_2.png) [@Yllaria](https://boards.straightdope.com/u/Yllaria)\ **Post date:** [September 15, 2014, 6:49pm UTC](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573/21 "2014-09-15T18:49:19Z")
I got it wrong and I’ve had three kids. I tried guessing average baby head circumference and divided by pi, but either that’s not the way to do it or my guess was off. It’s been awhile. During the event what you really want to know is when you’ll go to the delivery room (if that’s the way it’s still done) and when will it be over. Counting down with centimenters doesn’t really give you either, it just reassures you that progress is being made. The measurement that you want isn’t a number - it’s the word ‘crowning’. And sometimes that countdown can go: 2 – 3 – 4 – crowning! ---
**Author:** ![Renee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/renee/32/287_2.png) [@Renee](https://boards.straightdope.com/u/Renee)\ **Post date:** [September 15, 2014, 6:54pm UTC](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573/22 "2014-09-15T18:54:13Z")
I guessed nine. I thought it was nine or ten, picked the wrong one. Childless woman. ---
**Author:** ![Jonathan\_Chance](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jonathan_chance/32/701_2.png) [@Jonathan\_Chance](https://boards.straightdope.com/u/Jonathan_Chance)\ **Post date:** [September 15, 2014, 7:06pm UTC](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573/23 "2014-09-15T19:06:05Z")
Father of two who participating in both deliveries. I got it right. There’s a lot of chatter during delivery, especially towards the end. Keep your ears open and you might learn something. ---
**Author:** ![garygnu](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garygnu/32/2924_2.png) [@garygnu](https://boards.straightdope.com/u/garygnu)\ **Post date:** [September 15, 2014, 7:32pm UTC](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573/24 "2014-09-15T19:32:03Z")
Not exactly obscure knowledge, and an easy-to-remember number, too. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [September 15, 2014, 8:28pm UTC](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573/25 "2014-09-15T20:28:40Z")
> [@CrazyCatLady](#): > > Obscure? Really? I take it you never watched _ER_ or _Scrubs_ or basically any medical tv show ever? Because they all at some point mention this fact. All of them. The only thing I’ve ever learned from medical shows is that it’s never lupus. ---
**Author:** ![raspberry\_hunter](https://avatars.discourse-cdn.com/v4/letter/r/b19c9b/32.png) [@raspberry\_hunter](https://boards.straightdope.com/u/raspberry_hunter)\ **Post date:** [September 15, 2014, 8:37pm UTC](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573/26 "2014-09-15T20:37:46Z")
I know, but I’ve had a kid. I had no idea before my first pregnancy. (I also never really watched a bunch of medical drama shows, so.) I definitely didn’t know before having the first kid that you could totally be dilated 3cm (and more!) for days on end before having enough contractions that you needed to go to the hospital. I told my husband recently that someone we know who was having a baby was 4.5 INCHES dilated before she went to the hospital. Obviously just a brain fart on my end with respect to the units – and I certainly did get a pretty incredulous look from my husband: “umm… that’s quite a lot… wouldn’t she have had the baby by now, in that case??” ---
**Author:** ![Just\_Asking\_Questions](https://avatars.discourse-cdn.com/v4/letter/j/ba9def/32.png) [@Just\_Asking\_Questions](https://boards.straightdope.com/u/Just_Asking_Questions)\ **Post date:** [September 15, 2014, 9:03pm UTC](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573/27 "2014-09-15T21:03:40Z")
> [@Grumman](#): > > The thread title is misleading - my answer is “No”. yeah, where’s the poll option for “haven’t even a clue”? I know lots of obscure facts, just not that one. ---
**Author:** ![Sattua](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sattua/32/11906_2.png) [@Sattua](https://boards.straightdope.com/u/Sattua)\ **Post date:** [September 15, 2014, 9:05pm UTC](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573/28 "2014-09-15T21:05:53Z")
Did you watch Star Trek: The Next Generation? Do you remember Lieutenant Worf saying “congratulations, you have fully dilated to ten centimeters. You may now give birth.” I thought that would have come up in this thread before now. Or did it? I skimmed. ---
**Author:** ![Just\_Asking\_Questions](https://avatars.discourse-cdn.com/v4/letter/j/ba9def/32.png) [@Just\_Asking\_Questions](https://boards.straightdope.com/u/Just_Asking_Questions)\ **Post date:** [September 15, 2014, 9:14pm UTC](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573/29 "2014-09-15T21:14:55Z")
> [@Sattua](#): > > Did you watch Star Trek: The Next Generation? Do you remember Lieutenant Worf saying “congratulations, you have fully dilated to ten centimeters. You may now give birth.” > > I thought that would have come up in this thread before now. Or did it? I skimmed. I did, and I remember that episode. I guess I just don’t know nuttin’ ‘bout birthin’ babies. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [September 15, 2014, 11:59pm UTC](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573/30 "2014-09-15T23:59:30Z")
> [@bup](#): > > Women probably just know whether or not they’ve borne children. They have many mysteries… Why would we “just know”? Women need to be taught that fact just as men do. The fact that women have more personal interest in knowing such a fact and thus might be more motivated to find it out prior to giving birth than a man would is largely irrelevant. For the record - a woman who has never given birth, and couldn’t answer the question to save her life. I’ve just never needed to know that fact. ---
**Author:** ![elfkin477](https://avatars.discourse-cdn.com/v4/letter/e/a9a28c/32.png) [@elfkin477](https://boards.straightdope.com/u/elfkin477)\ **Post date:** [September 16, 2014, 12:03am UTC](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573/31 "2014-09-16T00:03:25Z")
Female, no children (yet). It’s 10cm, of course. I’ve probably heard this fact 150 times in books, movies, and TV shows so it’d be hard not to know it. ---
**Author:** ![Tamerlane](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tamerlane/32/7602_2.png) [@Tamerlane](https://boards.straightdope.com/u/Tamerlane)\ **Post date:** [September 16, 2014, 12:09am UTC](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573/32 "2014-09-16T00:09:29Z")
Childless male. I hadn’t a single solitary clue until I read this thread. And come to think of it, I guess I never have watched many medical procedural shows. No ER, no Scrubs. MASH when I was younger is about as close as I get ;). ---
**Author:** ![Asimovian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/asimovian/32/172_2.png) [@Asimovian](https://boards.straightdope.com/u/Asimovian)\ **Post date:** [September 16, 2014, 12:31am UTC](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573/33 "2014-09-16T00:31:03Z")
I was hoping for the “I haven’t got a clue” option in the poll. I wasn’t going to bother to guess, and I’ve seen the answer now. But I fully admit I didn’t have any idea. ---
**Author:** ![AClockworkMelon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aclockworkmelon/32/10803_2.png) [@AClockworkMelon](https://boards.straightdope.com/u/AClockworkMelon)\ **Post date:** [September 16, 2014, 12:37am UTC](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573/34 "2014-09-16T00:37:09Z")
> [@Tamerlane](#): > > Childless male. I hadn’t a single solitary clue until I read this thread. Ditto. Furthermore, I’ll probably have forgotten what the right answer is within a few days. ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [September 16, 2014, 12:45am UTC](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573/35 "2014-09-16T00:45:42Z")
> [@YogSosoth](#): > > I guessed. I really don’t know. Actually, funny thing is, I took out a ruler and looked at it. Then I estimated how big the baby’s head’s going to be and converted the inches to roughly centimeters (2.2 cen = 1 in?) Then I realized I don’t know what dilated really means, it can’t mean that the hole is opening up to 10 cen by itself right? Then I decided 10 was a nice, decent round number and stuck with it > > So did I get it right? 😃 You got it right. And yeah, it does open up to that, or roughly that. It doesn’t do it alone, of course. First the pressure from the baby’s head opens it some, like the foot of your sock when you push your foot down in there. Then the uterus conctracts, and sort of pulls the cervix up and open. It’s really hard to describe, but very obvious when you see an animation of it. The part you see pulling back around the 20 second mark is the cervix. The hole where the cervix isn’t is the hole we’re talking about getting to be about 10cm across. [spoiler][https://www.youtube.com/watch?v=odS3heDlshA[/spoiler]](https://www.youtube.com/watch?v=odS3heDlshA%5B/spoiler%5D) ETA: Added a spoiler box to 2 click the link. That video is animated and safe for work, but as soon as that video ends, decidedly NSFW ones pop up on preview. ---
**Author:** ![Sunny\_Daze](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunny_daze/32/438_2.png) [@Sunny\_Daze](https://boards.straightdope.com/u/Sunny_Daze)\ **Post date:** [September 16, 2014, 12:47am UTC](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573/36 "2014-09-16T00:47:21Z")
Female. During the event I didn’t really concentrate on the number. It’s pretty much “oh god when will this be over” The answer is “not soon enough”. ---
**Author:** ![Lord\_Feldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lord_feldon/32/341_2.png) [@Lord\_Feldon](https://boards.straightdope.com/u/Lord_Feldon)\ **Post date:** [September 16, 2014, 12:48am UTC](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573/37 "2014-09-16T00:48:46Z")
Male: No idea. I guessed the biggest because I figure a baby is a lot of stuff to squeeze out. ---
**Author:** ![wonky](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wonky/32/393_2.png) [@wonky](https://boards.straightdope.com/u/wonky)\ **Post date:** [September 16, 2014, 12:50am UTC](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573/38 "2014-09-16T00:50:58Z")
Not a clue. Not even a guess. ---
**Author:** ![Sattua](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sattua/32/11906_2.png) [@Sattua](https://boards.straightdope.com/u/Sattua)\ **Post date:** [September 16, 2014, 12:55am UTC](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573/39 "2014-09-16T00:55:57Z")
> [@Just\_Asking\_Questions](#): > > I did, and I remember that episode. > > I guess I just don’t know nuttin’ ‘bout birthin’ babies. I wasn’t responding to you specifically, but to the thread in general. Sorry if it came off that way. :smack: ---
**Author:** ![PSXer](https://avatars.discourse-cdn.com/v4/letter/p/48db29/32.png) [@PSXer](https://boards.straightdope.com/u/PSXer)\ **Post date:** [September 16, 2014, 12:57am UTC](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573/40 "2014-09-16T00:57:09Z")
I’m a guy and I had no idea I’ve watched every episode of The Cosby Show a lot and I don’t think they ever say the exact number [Previous page](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573.md?page=1) [Next page](https://boards.straightdope.com/t/do-you-know-how-many-centimeters-a-woman-has-to-be-dilated-to-give-birth/698573.md?page=3)