Babies use a set of coordinated movements and specific reflexes that allow them to participate in the birthing process. Adriana Lozada explains how this fascinating process works, and how it helps get them earthside.
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- Rethinking Second Stage: Letting Baby Out Versus Getting Baby Out, Gold Perinatal
- Your baby in the birth canal, Medline Plus
- Cardinal Movements (video), Spinning Babies
- Neuro/Reflexes, Stanford Medicine
- How to help your baby tuck their chin during labor, Mamaste Fit
Related Birthful episodes:
- Baby’s Position and Labor Flow
- Rethinking the Pushing Stage
- Your Baby, The Mammal
- Have an Easier Pregnancy (and Birth!) with Chiropractic Care
How Your Baby Helps During the Birthing Process
Adriana Lozada: Hello, hello, Mighty Parent or Parent-To-Be! Welcome to Birthful. I’m Adriana Lozada, and as we approach the end of our Birth Beyond the Clinical Experience series, I wanted to make sure we talked about how your baby helps during the birth.
And this is incredibly important, because they are as much of a participant in the process as you are. It’s a 50-50 partnership, and no matter how much you’ve prepared or what you’ve planned for your labor, if your baby has other plans, then they end up deciding the path you have to take. However, knowing the sequence of movements that your baby goes through during labor to help the birth process can give you more insights into how you can support both their physiology and your own.
And that’s a bit of what I wanted to get into during this short but powerful episode, which is a format that we do from time to time, where it’s just me on my own, diving deeper into topics that I find really fascinating and feel like you need to know about them.
And so yes, you heard me right: your baby helps during the birthing process, because they have to figure out how to wiggle and get through the tight squeeze that is the birth canal. And, truthfully, it’s a constant conversation between their body and your body (your uterus) to figure out what positions they have to get into and how to best navigate all of that. We know that they have a “biological mandate” to be born, like Whapio says, so there’s gotta be a lot of elements coming together to make sure that birth works.
And so for example, pelvic shapes may vary or the state of your tissues might be different, you might have tighter perineum, or ligaments that are tighter in the back, or maybe even positional habits of crossing your legs. That’s gonna create a space for a baby that’s very specific. And all of that will influence how baby starts out during labor and then what they need to do in order to get out.
However, in essence, the journey is kind of the same for all babies. It involves getting into the pelvis, working their way down, and then navigating the curve created between the tailbone and the pubic bone so that then they can make their grand exit.
Now, it is important to note that the more aligned and balanced and supple your tissues and bones are, the easier the conversation between your baby and your body. If they find that there’s a lot of tension on one side and they wanna go to that side, it’s gonna be harder for them!
So the better balanced your tissues can be, the better the space available for your baby to get into an optimal position. And if they are in an optimal position, then the labor will then flow easier as well.
So in terms of that initial position, you can have a baby that’s head-down, a baby that is head-up (so in a breech position), or even a baby that’s kind of sideways (although that sideways gets resolved ideally by 29 weeks). Because the art of vaginal breech deliveries has been dwindling, you usually want a baby that is head-down if you want a vaginal delivery.
So then, okay, the head is down. Now we’ve gotta look at the body. You can have a baby that is in an “anterior” position, which just means that their back is towards your front, or a baby that is “posterior,” you might have heard that as a baby that’s “sunny side up,” and in that case, their back is towards your back.
In terms of an optimal starting position, we usually think about a baby that is head-down, with their back towards your front. So in an anterior position, and even anterior left. So, with their back towards your left front side can be easier for the birth to flow. That isn’t to mean that if they’re on the right side, they can’t be born, or if they’re posterior (so with their back to your back), they can’t be born, it just means that it’s gonna take a little bit more wiggling and a little bit more time to get into the position that will allow them to come out.
And then the third thing that we kind of look at is the angle of the head. Is this a head that is tucked and aligned with the spine? Is it a head angle that has a little bit more of a tilt, like say with the ear closer to the shoulder, a bit off center. And that is called an “asynclitic” position. And sometimes if you have a hand under the chin or by the cheek or over the eye near the head, that would then be a “compound presentation,” which also tends to have an asynclitic position. And having that hand there makes it a little bit harder to navigate the birth canal as well.
So then once labor approaches or gets started, some of the very well-known movements that babies make to help be born, are what are called “the seven cardinal movements of labor.” The first one is called “engagement,” and that happens when your baby drops into the pelvis. And you might see this happen towards the end of your pregnancy. You see the belly like, “Oh, I dropped!” It’s also known as “lightening,” but sometimes it doesn’t happen until labor starts.
The second cardinal movement is “descent,” and it’s really a continuous occurrence. The baby descends to engage into the pelvis and then keeps descending all the way out. And that descent is usually measured by determining what’s called the baby’s “station”— and that needs to be done with a vaginal exam, but basically a baby whose head is up high (has not engaged), will have a station of like -4/-3/-2 as they make it into the inlet of the pelvis. And then, in the mid-pelvis, it’s more like a -1/0/+1. And then as baby keeps descending, you’ll get a +2/+3. Head is starting to crown, maybe +4— baby is out! So if you’re having vaginal checks, that station is a really good number to understand where in the canal your baby’s head is located.
The third cardinal movement is “flexion,” which just means that the baby’s chin is flexed into their chest. And the purpose of this is to have the top of the head, the crown of the head, be the leading part as they go down the birth canal. And that has a smaller diameter, so really it’s about being gentle into showing a smaller part of the head. And that flexion is kind of initiated by that conversation with your tissues, because as the baby is descending and your tissues are hugging their head, the normal movement is to have that chin tuck as their head is enveloped— kind of like imagine putting on a turtleneck, they’re more difficult if you keep your head straight when you’re doing your turtleneck, you tend to flex as the turtleneck is coming down.
Now, usually the top of the pelvis (the “inlet”) tends to have more space side-to-side, and then the “outlet” (the bottom of the pelvis) tends to have more space front-to-back. And so babies usually, as they’re getting into engaging into the pelvis, they might be looking towards your hip, because their head is sideways and that’s independent from the body, right? The body does follow, but their body can still be towards the front with the head to the side, because our heads rotate.
So they come in looking towards the hip, and then when they get to the mid-pelvis, the fourth cardinal movement is one of “internal rotation.” They have to rotate the head so that then it’s aligned with the pelvic outlet that they are arriving at, which is wider front-to-back.
And, ideally, the head is rotating in a way that the back of their head is towards your front. After internal rotation, the next cardinal movement is “extension,” when babies extend their heads back, again to navigate that curve between the pubic bone and the tailbone. And that really is when you’re like, “There’s baby!” and you’re definitely pushing and you can start seeing some of baby’s head coming out. Then— boom!— the head comes out.
And then you have “external rotation,” which is where the baby rotates so that the shoulders can align front-to-back with that wider outlet. And then they come out. And then the seventh cardinal movement is “expulsion,” where the rest of the body comes out.
So those are the cardinal movements: engagement, dissent, flexion, internal rotation, extension, external rotation, and expulsion. But that’s not all the ways that babies help to be born. They also have some reflexes that help in the wiggling down and out through the process.
And you will see these reflexes once your baby is born, because they still have to manifest to provide coordination, and later be integrated into great purposeful movements like crawling or walking or skipping. And babies have a bunch of primitive reflexes, but in terms of how they help to be born, there are four that I’m gonna mention.
One is the “asymmetric tonic neck reflex,” also known as “the fencer.” And this is what helps babies corkscrew out of the birth canal. And it basically— when you have their head moved to one side, the leg and the arm on that side extend, and the leg and the arm on the other side bend— so they look like a fencer, right? En garde!— that kind of position. So that helps them rotate through the pelvis.
Another cool reflex that comes into play is the “Galant reflex,” also known as the “truncal incurvation reflex.” And that one is basically if you stimulate one side of the baby’s spine, their hip and neck flex towards that side. So this Galant reflex really helps, especially at the beginning, to have that chin tuck and have them be curled up in a C position, be really small as they start making their way into the pelvis.
Now another thing you’ll see with your baby is if you hold them in the back of the head, they will push back and try to extend the head, and it’s more of a reflexive action with any of us. If you push your head forward and get it really flexed to the chin, instinctively, we’re gonna wanna move that head back to be better, properly aligned. Our heads are not supposed to be flexing towards the chin, so as the baby moves down the canal, it’s constantly trying to like also move that head back, move that head back, and when it gets to the position where there’s the curve between the pubic bone and the tailbone, finally, there’s part of that canal that is soft in one end, right? Because pubic bone is hard, tailbone is hard, and they’re trying to extend the head back… extend the head back… and suddenly they go past the pubic bone and ha! They can extend the head.
There’s another reflex that also comes into play to help with that, which is the Perez reflex. So, the vaginal canal is stimulating both sides of the spine, and so they’re gonna want to extend their head and extend their sacrum (like, move their butt out). And this makes them form into an S shape, which is really nice because they’re further down. They have descended quite a bit into the pelvis and are basically at the outlet. And at this point, a large part of their bodies is out of the uterus. It’s… a lot of it is in the vagina.
So, this unfurling of this S shape brings us into pretty much my favorite reflex, which is the “stepping reflex.” Now, the stepping reflex, you’ll see it with your newborn if you stand them up and something comes into contact with their feet, they’re gonna push off and bounce. And you can have them like bounce, bounce, bounce on your lap. If you do it more gently, they will simulate walking— so, one foot will come up, the other foot will come up, and it’ll be more of an asymmetrical movement. But if you do both at the same time, there’s this bounce, bounce, bounce that happens.
So as they are unfurling themselves out of the uterus into the vagina, and so your uterus has more access to the bottom of their feet and is contracting against the bottom of their feet, they’re gonna bounce against that, in essence, trying to launch themselves out of your vagina. So, while the baby is activating that stepping reflex, as your uterus touches the bottom of their feet and they’re trying to launch out your body, if you have been supporting physiology and have immense surges of oxytocin going through your body, you’re gonna have these really great strong contractions that are helping do the seventh cardinal movement, right? The expulsion of the baby. And this is a reflex that your body has, this “fetal ejection reflex,” basically to involuntarily expel your baby out of your body. If you do support the physiology, then you might get a chance to experience that fetal ejection reflex.
So then how can you help your baby as they move through the birth canal?
Well, first of all, during pregnancy you can balance your tissues and do a lot of movement! And to start you off, you can listen to the episode that I did with Gail Tully from Spinning Babies, on baby’s position and labor flow.
Now, during the birth, you can mimic what your baby is doing and move, move, move, move! Even with an epidural, move as much as you can ’cause that is gonna create more space and openings for baby to wiggle. Remember that gravity is your friend! So use upright positions to help baby come down.
And then if you do have vaginal checks, ask about more than dilation. What’s your baby’s station? Where are they at? That will let you know if the baby is coming down. And if not, why not? Ask about your baby’s body position. Let curiosity guide the process. And remember: If your baby doesn’t start in the best position, then move, move so that you can give them more space, to switch into a position that will allow things to flow better.
Also, remember that your baby’s bony plates of the head are not fused, so that it can mold and let them go through tighter squeezes, and that you have relaxed in going through your pelvis. So that your pelvis can also create more space if needed. But if you wanna create space, you gotta move, move, move!
You can connect with Birthful on Instagram @birthfulpodcast. And if you really enjoyed this episode and want to learn more about how to best support your physiology during birth, go to birthfulcourses.com to learn more about my birth and postpartum preparation classes. Another great way you can support the podcast is by trying out any of the wonderful products made by our sponsors. This is what allows us to continue doing this work.
You can find the in-depth show notes and transcript of this episode at birthful.com, where you can also download your free postpartum preparation plan.
Birthful is created and produced by me, Adriana Lozada, with production assistance from Aysia Platte. This episode was produced in part by LWC Studios: Paulina Velasco, Jen Chien, Cedric Wilson, and Kojin Tashiro. Also, a big shout out to perinatal professionals Barbara Harper and Pat Predmore for providing their expertise as I researched this episode.
Thank you so much for listening to and sharing Birthful. Be sure to follow us on Goodpods, Spotify, Apple Podcasts, Amazon Music, and everywhere you listen.
And then come back for more ways to inform your intuition.
Lozada, Adriana, host. “How Your Baby Helps During the Birthing Process.” Birthful, Lantigua Williams & Co., May 24, 2023. Birthful.com.
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