The 9 Structures of the Pelvis Every Pregnant Mama Should Know

Pregnancy changes everything.

Your center of gravity shifts. Your ligaments become more flexible. Your belly grows. Your posture changes. And your pelvis—the foundation supporting all of those changes—has to adapt right along with you.

That’s why pelvic balance matters so much during pregnancy.

And this is where the Webster Technique comes in.

A common misconception is that Webster Technique is simply about “turning breech babies.”

It’s not.

We’re not turning your baby. We’re working with Mom’s body to create a more balanced pelvic environment so baby has the opportunity to find their own best position. 

So let's talk about the pelvis and the structures we care about.

Your Pelvis Is More Than Just Your Hip Bones

When we talk about pelvic balance, we're not talking about one bone being “out.”

The pelvis is a complex structure made up of bones, joints, muscles, and ligaments that all have to work together.

When one area becomes restricted or another area becomes excessively tight, it can influence how the entire system moves.

Here are 9 important structures we think about when looking at pelvic balance:

1. The Sacrum

The sacrum is the triangular bone at the base of your spine that sits between the two sides of your pelvis.

It's a major focus of the Webster Technique because the way the sacrum moves influences the biomechanics of the entire pelvic region.

2. The Right SI Joint

The sacroiliac—or SI—joint connects the sacrum to the right side of the pelvis.

During pregnancy, the SI joints have to accommodate changing loads and movement as your body adapts.

3. The Left SI Joint

Same idea on the other side.

We want the right and left sides of the pelvis to work together as efficiently as possible rather than having one side carrying significantly different loads or moving differently.

4. The Pubic Symphysis

This is the joint at the front of the pelvis where the two pubic bones meet.

As pregnancy progresses, hormonal and mechanical changes can affect the tissues surrounding this area, and some pregnant women experience discomfort around the pubic symphysis.

5. The Sacrotuberous Ligament

This strong ligament connects the sacrum to the pelvis and is one of the soft-tissue structures considered in Webster work.

Reducing excessive tension in the surrounding tissues can help support more balanced pelvic mechanics.

6. The Round Ligaments

The round ligaments help support the uterus and extend toward the front of the pelvis.

As the uterus grows, these ligaments stretch and adapt.

That stretching can contribute to the pulling or sharp sensations many moms recognize as round ligament pain.

The Webster approach may include gentle soft-tissue work around structures such as the round ligaments to help reduce tension.

7. The Iliopsoas

The iliopsoas is a major hip-flexor muscle that connects the lower spine and pelvis to the femur.

Because it crosses the pelvis and hip, tension in this muscle can influence pelvic mechanics.

That's why the surrounding musculature matters just as much as the bones.

8. The Piriformis

The piriformis is a deep muscle in the buttock region that connects the sacrum to the upper femur.

It plays a role in hip movement and pelvic mechanics, so assessing the surrounding musculature can be an important part of looking at the whole picture.

9. The Pelvic Floor

And then we have the pelvic floor.

These muscles form the bottom of the pelvic cavity and work with the rest of the pelvis to provide support and stability.

This is one reason we don't want to think about the pelvis as simply “a bone that needs to be put back into place.”

It's a system.

Bones, joints, muscles, and ligaments all have to work together.

So Where Does Webster Technique Fit In?

The Webster Technique is a specific chiropractic analysis and adjustment approach used during pregnancy.

At its core, it focuses on pelvic balance and sacral biomechanics, along with the surrounding muscles and ligaments.

The goal isn't to force the pelvis into a particular position.

The goal is to identify areas of restriction or imbalance and use gentle, pregnancy-appropriate care to support better movement and balance.

Think about it like this:

We don't move the baby.

We create a better environment for the baby's movement.

That's a very different conversation.

What About Breech Babies?

This is probably the question we hear most.

“Can Webster turn my breech baby?”

Our answer is:

That's not what the technique does.

Webster Technique does not involve manually turning the baby or performing an external cephalic version.

Instead, the approach focuses on the mother's pelvis and the surrounding soft tissues. The theory is that reducing biomechanical restriction may give the baby more freedom to move and find their own position.

And that's an important distinction.

We don't promise that a baby will turn.

We don't guarantee a particular birth outcome.

We support Mom's body and let Mom and baby do what they are designed to do.

And You Don't Have To Have a Breech Baby to Benefit From Pelvic Care

This is another big misconception.

Webster Technique isn't only for moms whose babies are breech.

Pregnancy itself puts tremendous demands on the pelvis.

As your belly grows and your center of gravity changes, your body has to continually adapt.

That can mean more stress around your:

• Low back

• Hips

• SI joints

• Pelvis

• Round ligaments

• Pubic symphysis

• Surrounding muscles

A balanced, mobile pelvis can be an important part of helping your body adapt to those changes.

Your Body Was Designed for This

Pregnancy is incredible.

But “your body was designed for this” doesn't mean your body shouldn't need support.

Think about an athlete.

They don't wait until their body completely breaks down before taking care of it.

They train.

They recover.

They strengthen.

They get adjustments.

They pay attention to their mechanics.

Pregnancy deserves that same level of intentional care.

Your body is doing something extraordinary.

Let's support it while it does it.

And that's why we love prenatal chiropractic care and the Webster Technique.

Not because we're trying to control pregnancy.

Not because we're trying to turn babies.

Not because we're promising a particular birth outcome.

But because we want to help moms feel supported, balanced, and confident in their changing bodies.

Mom's body. Mom's pelvis. Mom's nervous system. Baby gets to do the rest. 

This article is for educational purposes and isn't a substitute for individualized prenatal or medical care. Webster Technique should be performed by a chiropractor appropriately trained in prenatal care. If you have concerns about fetal position, pelvic pain, bleeding, contractions, or other pregnancy symptoms, contact your OB or midwife.