Why Your Push Position Matters More Than You Think
You Don't Have to Push Flat on Your Back
Picture this: you're fully dilated, you've been laboring for hours, and the nurse says "okay, time to push." Without thinking twice, you're flipped onto your back, feet in stirrups, chin to chest, told to hold your breath and push like you're having a bowel movement.
Sound familiar? That's the default in a lot of hospital rooms — not because it's the best option, but because it's the easiest one for everyone else in the room.
Here's what I want you to know before you're in that moment: your pelvis is not a fixed, rigid structure. It moves. It shifts. It opens differently depending on how you're positioned. And the position you push in can directly affect how much room your baby has to come through.
This isn't about being anti-hospital or difficult. It's about understanding your own anatomy well enough to make informed choices — and knowing that "endless options" isn't just a nice phrase, it's biomechanical fact, even if you have an epidural.
In this post, you'll learn:
Why your pelvis isn't one fixed shape — and what "pelvic outlet" actually means
What a "free sacrum" is and why it matters for pushing
How different pushing positions change your pelvic dimensions (with the research to back it up)
Why an epidural doesn't mean you're stuck on your back
How to start practicing these positions now, before labor day
Let's get into it.
Your Pelvis Is Dynamic, Not Fixed
If you took anatomy class and pictured the pelvis as one solid bone, I get it — that's how it's often taught. But your pelvis is actually made up of multiple bones connected by joints and ligaments that have some give, especially during pregnancy when relaxin and other hormones increase ligament laxity.
That means the shape of your pelvic outlet (the lower opening your baby travels through) can actually change depending on your position. A computational modeling study found that maternal joint loading in an upright birthing position, such as squatting, could open the outlet of the birth canal, and dynamic movement may create even greater pelvic mobility than holding a static position.
In that same study, researchers found something especially relevant to pregnant bodies: pelvic outlet diameters increased by 6.1 mm and 11.0 mm (front-to-back and side-to-side) during a squat for pregnant participants — compared to much smaller increases of 4.1 mm and 2.6 mm for non-pregnant participants — and these differences were considered clinically meaningful.
Translation: pregnancy hormones + the right position = real, measurable extra space for your baby. That's not "woo." That's biomechanics.
Research using MRI has backed this up too — compared to lying on your back, the pelvic outlet measurements actually become wider in squatting and kneeling positions.
So when I say "position matters," I'm not talking about comfort preferences (although comfort matters too). I'm talking about literal millimeters of extra room for your baby's head to navigate through.
What Is a "Free Sacrum" — And Why Should You Care?
Your sacrum is the triangular bone at the base of your spine, right between your hip bones. It forms the back wall of your pelvic outlet.
Here's the key thing: the sacrum can move. It can tilt and shift backward (nutate/counternutate, if you want the technical terms) to increase the space in your pelvic outlet. The widest diameter of your pelvic outlet — the front-to-back measurement — exists specifically because the sacrum and coccyx can move backward to create more space during pushing.
But here's the catch: your sacrum can't move if you're lying flat on it.
When you're flat on your back with your weight pressing directly into your sacrum and tailbone, you're essentially pinning that bone in place. It can't shift backward to make room, because your own body weight is blocking it.
This is why so much of birth position research groups together what's called "flexible sacrum positions" — things like hands and knees, side-lying, kneeling, and squatting — versus "non-flexible sacrum positions" like lying flat on your back. A 2020 systematic review and meta-analysis found that flexible sacrum positions were superior for promoting maternal wellbeing during childbirth, while noting that more high-quality research is still needed to fully understand the magnitude of the effect.
Other researchers explain it simply: flexible sacrum positions — like kneeling, hands and knees, sitting on a birth seat, and side-lying — take weight off the sacrum, which allows the pelvic outlet to expand.
So the question to ask yourself isn't "is this position comfortable?" (though that matters). It's: "is my sacrum free to move, or am I lying on it?"
The Possibilities Really Are Endless — Yes, Even With an Epidural
I know what you might be thinking: "Okay Kelsey, that's great, but I'm planning on an epidural and I won't be able to feel my legs, let alone get into some fancy position."
Fair. But here's the thing — having an epidural does not mean your only option is flat on your back with your knees in stirrups. It just means you'll likely need help getting into and holding other positions.
A few research-backed options for laboring and pushing with an epidural:
Side-lying with a peanut ball. This is one of the most well-studied options for epidural birth. The peanut ball sits between your legs to keep them apart, which helps maintain an open pelvic outlet to support fetal descent — something that's especially valuable for women with epidurals, who have fewer position options available to them. One small randomized study found peanut ball use after epidural placement was associated with a 113-minute reduction in total labor time and a 57% reduction in cesarean rate — researchers themselves noted that if replicated, a result like that from such a simple, low-cost tool would be a big deal.
Side-lying, period. Even without a peanut ball, side-lying allows more sacral movement than back-lying. As one nurse-midwife put it plainly: side-lying works whether you've had an epidural or not.
Hands and knees / all fours (with support). This can be modified for an epidural — most women will need help getting into this position and maintaining continuous fetal monitoring, but it's absolutely possible.
Asymmetrical positions (one leg up, one leg down). Even propped in bed, shifting one leg higher than the other can help open the midplane of the pelvis and optimize how contractions are working.
Seated upright with the foot of the bed dropped. This can allow the pelvis to open more than flat lying — though one source notes this position generally shouldn't be held longer than 20–30 minutes, since it may reduce how well the epidural is working.
The bottom line: an epidural changes how you get into a position and who helps you get there. It doesn't eliminate your options. Your nurse, midwife, or OB can help you reposition — but only if you (and they) know it's worth doing.
Why "Practice Makes Perfect" Applies to Pushing Too
Here's where my athlete brain comes in. You wouldn't show up to race day having never practiced your nutrition strategy, your pacing, or your gear. So why would you wait until labor day to find out what your body — and specifically your pelvic floor — does in different positions?
Your pelvic floor is a group of muscles. Like any muscle group, it responds differently depending on the position your body is in. Some positions make it easier to relax and lengthen those muscles (which is exactly what you want during pushing). Others put you in a position where you're more likely to clench, brace, or fight against your own anatomy without realizing it.
This is something you can start exploring well before your due date, ideally with guidance from a pelvic floor physical therapist who can help you actually feel the difference.
Some things to start experimenting with now:
Hands and knees — notice how your low back and pelvis feel here compared to sitting
Deep squat (supported) — using a wall, your partner, or a sturdy piece of furniture, notice what happens through your hips and pelvic floor as you sink down
Side-lying with a pillow or peanut ball between your knees — get familiar with this position now so it's not brand new on labor day
Practicing a relaxed exhale/pelvic floor release in each of these positions — this is the opposite of the "hold your breath and bear down" cue, and it's worth understanding both approaches before you're in the moment
The goal isn't to memorize a "perfect" position to use on the day. It's to build body awareness so that when you're in labor — tired, possibly with an epidural, definitely not in the headspace to learn something new — your body already has a felt sense of what opening up versus bracing feels like.
This is exactly the kind of training I walk clients through, both one-on-one at enCORE Therapy and inside the birth prep work I'm building for moms who want this kind of preparation. Evidence-based birth prep, Kansas City and Overland Park, isn't just about knowing facts — it's about training your body to use them.
Putting It All Together
Let's recap what the research actually shows:
Your pelvis is dynamic — its dimensions change based on your position, and pregnancy hormones make this even more true for you right now.
Your sacrum needs room to move — and lying flat on your back pins it in place, working against you instead of for you.
You have more options than you think — including with an epidural, where side-lying, peanut balls, hands and knees, and asymmetrical positions are all supported by research.
Your pelvic floor is trainable — and the time to start feeling what different positions do for your body is during pregnancy, not during transition.
None of this means any one position is "right" and another is "wrong." It means you have options, and knowing about them ahead of time means you can actually use them — and ask for them — when it counts.
Ready to Train for Your Birth Like the Athletic Event It Is?
If this is the kind of education you wish someone had handed you before your first birth (same, honestly), this is exactly what I work on with clients at enCORE Therapy. Whether you're local to Kansas City or Overland Park or working with me virtually, pelvic floor physical therapy isn't just for postpartum recovery — it's part of how you prepare for the big day.
Want to start training now? Reach out to learn more about pelvic floor therapy and birth prep sessions, and let's get your body ready for whatever position works best for you on the day.
I'm Kelsey — pelvic floor PT, athlete, and certified birth biomechanics nerd helping moms in Kansas City, Overland Park, and virtually prepare for birth and postpartum with evidence-based education that actually makes sense 🤍
