What happens to your cervix during birth: video

Daphne [holding a doll]: We're going to talk about how the cervix opens during labour, and makes space for the baby to get through. But first of all I want you to think back to before you were pregnant: all that way back. Then, your uterus or womb was about the size and shape of this pear [holds up a pear]. If you just hold that low down on your bump, [Emily places the pear on the front of her tummy over the lower part of her bump], that's about where the womb is, and that's about the size it was before you started, and now of course it's grown to this size, to take this lovely baby inside, so it's stretched, and made space for your baby. And the cervix is the bit of the uterus at the end, the neck of the womb that has to now stretch and open up and make space for your baby to get through and get born.

[Emily nods in agreement]

I just want to do a little exercise. I'd like you to feel your nose [Emily touches her nose] and now feel your lip [Emily touches her bottom lip]. And what's the difference?

Emily: My nose is a lot harder and the lip is softer.

Daphne: And stretchier. Yes. And the cervix, which has to open to make space for your baby, starts out like your nose; firm and muscular. And if you could see it end on, it would look like a cotton reel: a circle with a little tiny hole in it. And that little tiny hole has to open right out to about 10cm to get the baby through. So at the first bit of labour, the first perhaps third of labour, is about you secreting hormones to help the cervix soften. So it changes from this texture [points to nose], to this soft stretchy texture [touches lip].

[Emily nods]

Labour is frustrating sometimes for first-time mothers, because it takes such a long time to go from this texture [touches nose] to this texture [touches lip]. And it's a bit like blowing up a balloon. When you first blow up the balloon, [begins to inflate a party balloon], it's quite hard to get any air into it, because it's quite firm, but actually, after a little while, once you've stretched it, you can blow much more easily [continues to blow up balloon]. And the same thing happens with the cervix. It starts off slow, but as it gets softer and stretchier it opens more easily.

So now we're going to look at the baby inside the womb. I've got a pair of stretchy leggings here, which is going to be a substitute for the womb, and we're going to pop the baby inside [puts leggings over the baby doll's head]. So here's the baby inside the uterus, all tucked up nice and safe, and then here's the cervix, which is like a neck [gathers the bottom of the leggings around the baby doll's head], a tube, to begin with, and the baby's in there, doesn't quite know where it's going because it can't see anything, but it's going to come out and be in your arms very soon. So you have a contraction, and the contraction pulls on these muscles here and opens the cervix a little bit [opens up leggings] and then when the contractions finish, the cervix goes back a bit, but not quite as far as it was. So every contraction opens up the cervix a little bit, pulling it open, letting it go back, opening it with the next one, making a bit more space, and then eventually the baby's head starts to come through the cervix, and so you're about half way here, probably about 4cm.

And then another contraction comes along and opens the cervix a bit more, and then when it stops it fades away and the cervix goes back a bit. And eventually, the cervix gets to 10cm [pushes the doll's head part-way through the end of the leggings], which is about the baby's ear level, and the baby's head can come right through the cervix. So that would be fully dilated, the end of the first stage of labour and ready for the second stage, which is when you can push the baby out.

Now occasionally, you get a bit of the cervix that gets left behind, and that's called an anterior lip. And it's usually at the front, or the anterior, because by this stage the baby's well down in your pelvis, and the head is up tight against the pubic bone [holds baby doll inside a model of a pelvis]. And it's easy for the cervix to get stuck there if you're lying down, and because it's like your lip, you'll know that if you bruise your lip, it tends to swell, so if you push against an undilated cervix, it'll tend to cause it to swell, which is why your midwife will say "Don't push".

She's waiting for that cervix to get out of the way, so you're ready to push, and you can help it by changing your position. Stand up, go to the loo, walk around, or turn over onto all fours, because what that does, is that it allows the baby's head to drop off the public bone, and once it's moved away from the pubic bone, it's much easier for the cervix to come back up [moves doll away from the pelvis]. And then, when you're fully dilated, the midwife will say "Yes, you can push", but actually, your body will tell you that you're ready to push. You'll have a very strong pushing urge, and that helps you to push the baby down. You lean forwards, you use the air in your lungs and your weight to help push the baby into the pelvis [moves baby doll through the pelvis].

So you'll have a contraction, and you may find that you're making a lot of noise. A lot of women need to make a noise when they push. A bit like tennis players who grunt! Or weight-lifters! So you lean forward and you go "Ugh!" and you make this big grunting sound, and you think: "Who is making that noise?" And then you realise it's you! But with each contraction the baby comes further and further down into the pelvis, and you can feel the birth canal opening and making space for the baby with each contraction. It opens and then closes [moves hands over the top of the baby doll's head, opening and closing them] and then opens, and then closes [repeats process]. And it may be that your labour partner says: "I can see the head! I can see the head!" And at the peak of the contraction they will be able to see the head. You can reach down and feel the head, but it then closes up again when the contraction goes away.

But eventually, you get to the point where the head doesn't slip back any more, and this is called crowning. And your tissues are all stretched to the maximum at this point, so they're stretched here, and they're stretched here [moves fingers over the top of the doll's head], and that's actually the point of greatest stretch, and you often get a very strong burning sensation. A midwife may say: "Right, don't push, pant. Don't push", or, "Stop pushing." It's because she wants you to pant the baby out, to get the baby born gently. So you'll go "Huh, huh huh", [makes panting noises] and pant the baby out. And then the baby turns as he comes, so you can see the profile of your baby's face.

So, to get there, you've actually got to push really hard, but then you've got to be really gentle with that panting, and that can be really difficult. But there's a little exercise you can do at home that will help prepare you for it. I'm just going to hold up a mirror [holds a mirror up to Emily's face], so that you can see in the mirror, and you remember when you were children and you made faces at each other? Just pull the sides of your lips and make a face into the mirror until you feel that burning sensation on the edges? Yes? You can feel it? OK. That's just the sensation you get when the baby's head is crowning. And if you know what it is, you can relax and pant the baby out. If you don't know what it is, you'll go "Ooh, it's horrible! I don't want to do it!" So if you practise a few times when you're cleaning your teeth in the morning, just pull at the sides of the mouth, and you'll really understand what that sensation is like and why the midwife is saying don't push. Because it'll help protect your tissues, help prevent tearing, and it also eases your baby gently into the world, so that you can then turn and see him!