"MUM BUM" and Why you Can't Blame the Jeans

buff muff app exercises mum bum postpartum Jan 14, 2020

Woman performing a glute bridge exercise on a white rug, lifting her hips off the floor to rebuild glute and pelvic floor strength after pregnancy

By Kim Vopni, The Vagina Coach — Certified Pelvic Floor Fitness Specialist · Published January 14, 2020

Direct Answer

"Mum bum" isn't caused by your jeans — it happens when pregnancy shifts your posture, encouraging you to tuck your tailbone and lean on your lower back instead of your glutes, which flattens and weakens the backside over time. The fix is retraining posture, adding glute-focused movement like bridges and walking, and coordinating kegels with your breath, not switching pants.

Key Takeaways

Pregnancy posture changes, not your jeans, are usually the real cause of a flattened backside.
Prolonged sitting and tucking the tailbone under-use the glutes and flatten the pelvis over time.
Standing more, walking, and glute-focused strength moves like bridges help rebuild the backside.
Kegels paired with movement and breath, not kegels alone, support both pelvic floor and glute function.
Correcting posture and glute activation postpartum can also ease tailbone and low back discomfort.

5 Ways to Get Your Bum Back After Pregnancy

During pregnancy your centre of gravity shifts and many women try to counterbalance that shift by tucking their tailbone, overusing the posterior pelvic floor muscles and under-using the glutes.

This result is a flattened backside that can’t fill up a great pair of jeans – or even hold that pair of jeans up!

While it may seem a bit odd, next time you are at your mom group, check out your friend’s butts – what do you see? Or maybe the better question is what don’t you see?

Chances are you will see a lot of flat bums, flatbacks and pants that are continuously being hoisted up. What you won’t see is much, if any, booty! Mum bum syndrome is rampant and below are some tips and exercises to help you get your booty back!

Stand Up

Sitting does nothing to build the glutes and everything to make it flat as a pancake and let’s face it, we spend a lot of time sitting these days don’t we? Minimizing the amount of time spent sitting is critical to maintaining a healthy backside!

Walk

To make up for the amount of time we spend sitting, many of us head to the gym to burn some calories while often choosing a high-intensity activity that may not be well suited to our body, especially after having a baby.

One of the best exercises out there is walking, particularly hill walking. Walking is low impact and when you add in the incline of a hill, it really blasts those glutes into high gear along with revving up the cardio!

Bridges

One of the best glute exercises out there is the bridge and this can be done during pregnancy with a wedge and as early as the 2nd week postpartum.

As your strength increases, you can also add some resistance with a sandbag on your pelvis and once your pelvic stability is on track you can also up the challenge by performing the movement with one leg off the ground and extended.

Hip Extensions

These can be done standing or on all fours (however I don’t recommend being on all fours during).

You don’t need a fancy piece of equipment – you can simply use your body weight or you can tie a theraband around your ankles to add some resistance.

Squats

Squatting is a great glute builder and is also a movement that will be done over and over and over as you bend down to pick up your babe or toddler (or their toys, or spilt food, or…).

Squatting can be done (and should be done) during pregnancy and within a few weeks postpartum. The range of motion can be modified but you want to aim for a nice deep squat with the tailbone un-tucked and your pelvis in neutral (keeping the small curve in your low back).

There are many glute exercises out there but these versions offer versatility both before and after pregnancy. They help maintain and build up the glutes while also encouraging the sacrum to stay un-tucked which is key to avoiding and curing mum bum syndrome!

Kegels

Kegels themselves are not a booty builder but Kegel Mojo exercise is! Kegels coordinated with movement (like the ones listed above) are a game-changer for optimizing core function and a side benefit is a fuller backside. Many of the participants in the 28 Day Kegel Challenge notice more fullness. I also recall a client of mine saying 'I came to see you because of my abs and I left with a butt - something I didn't know I needed but it has been a game-changer with how I feel and how I look'.

Ready for more guided support? Join the Buff Muff membership for pelvic-floor-friendly core and glute workouts, a 7-day starter challenge, and ongoing coaching to help you rebuild strength after pregnancy.

Frequently Asked Questions

What is "mum bum" and what causes it?
Mum bum happens when pregnancy shifts your posture, causing you to tuck your tailbone and rely on your lower back and hip flexors instead of your glutes. Over time this under-uses the glute muscles, leaving the backside flat no matter how many jeans you try.

Can kegel exercises alone fix a flat backside?
No. Kegels strengthen the pelvic floor but don't build glute muscle on their own. Coordinating kegels with movement, like bridges and glute-focused strength work, is what helps restore fullness and function together.

How soon after pregnancy can I start glute exercises?
Gentle glute activation, like the bridge exercise, can typically begin once you feel ready and have clearance from your care provider, starting slowly and watching for any pelvic floor symptoms like leaking or heaviness.

Do I need special equipment to fix mum bum?
No. Bodyweight exercises like bridges, squats, and step-ups, done with proper alignment and breath, are enough to start rebuilding glute strength and correcting the tucked pelvis pattern.

If you enjoyed this article, you might also like our episode:
The Importance of Posture For Pelvic and Whole Body Health with Esther Gokhale

Listen to the episode