Sit-Ups After Baby: What the Research Really Says

If you’ve ever asked whether it’s safe to do sit-ups after having a baby, you’ve probably had five different answers. Each one came from a different person.

Don’t do them, they’ll make the gap worse. Do them, they’ll close the gap. Avoid your deep core exercises, they’ll widen the gap. It’s a lot of noise for one simple question and most of it doesn’t line up.

There isn’t a single yes or no answer here. There’s a more useful and more accurate one and it starts with understanding what’s actually going on in the body.

Where the “No Sit-Ups” Advice Came From

Back in the late 1980s and through the 90s, research confirmed that most women get some degree of abdominal separation during pregnancy. That’s simply part of how the body accommodates a growing baby. Over time, that research shaped techniques built entirely around one goal: close the gap. If the gap got smaller, the approach was working. If it didn’t, it wasn’t.

That single measurement, gap width, became the whole story for a long time. Which is part of why the advice has felt so contradictory over the years. Everyone was chasing the same number, using different methods to get there.

What’s Actually Happening in the Abdominal Wall

The abdominal wall has four layers. Rectus abdominis down the front, external obliques on the sides, internal obliques underneath those and transverse abdominis running around from back to front. Down the middle sits a strip of connective tissue called the linea alba. That’s where separation happens as the abdominals stretch to make room for a growing baby.

Many trainers and mums have been told that activating transverse abdominis pulls the rectus muscles together and closes the gap. Its origin sits at the back and it inserts into the linea alba, so when it contracts, it pulls laterally and creates tension. That can actually widen the gap slightly rather than close it.

That doesn’t make transverse abdominis work pointless. That tension is what helps rebuild the connective tissue over time, in much the same way a muscle strengthens under progressive load.

Tension Matters More Than the Gap Itself

Recent research points to a distinction between tension and distortion in the linea alba.

Tension is what you want. It means the connective tissue is taut, capable of managing load and functioning the way it should.

Distortion is different. It’s when that tissue goes slack or floppy under load, even if the visible gap looks smaller.

A crunch will bring the rectus muscles closer together, but it can also increase distortion in the tissue between them. Transverse abdominis work might not narrow the visible gap as much, but it builds the kind of tension that helps the tissue actually function.

A 2025 meta-analysis of over 1,500 women found that isotonic exercises like crunches and leg raises do significantly reduce the gap and found no evidence that appropriately progressed sit-ups cause harm. The same research confirmed that the goal should be restoring both tension and function together, rather than chasing one measurement on its own.

So What Should You Actually Do?

Skip the rulebook. A framework works better than a rule, because every woman’s body, history and recovery timeline is different.

Start by understanding where she is right now. A thorough postpartum screening, checking for separation at both depth and width and observing what happens when she curls up without any cueing, tells you far more than a generic protocol ever could.

From there, build the basics. Teach pelvic floor connection first, then transverse abdominis activation and retest to see whether tension holds at the linea alba during movement. If it does, she may be ready to progress toward curl-ups and more loaded core work. If it doesn’t yet, that’s useful information, not a reason to avoid movement altogether. It simply means starting with breath, connection and functional patterns before adding load.

Watch for the signs that matter. Doming or coning during abdominal work, breath holding, or bracing patterns are all worth noting, not because they’re automatically a problem, but because they tell you whether the abdominal wall is managing pressure well.

And always keep pelvic floor in the conversation. A strong abdominal wall built without any regard for pelvic floor capacity isn’t the full picture. The two need to be considered together, every time.

Abdominal separation is a normal, expected part of pregnancy. Gap width alone was never the full story and chasing it in isolation left a lot of mums confused and a lot of trainers second-guessing themselves. The research supports progressive, individualised loading, built on a foundation of tension and function rather than fear.

If you’re a mum wondering whether sit-ups are off the table forever, they’re not. If you’re a trainer trying to make sense of the conflicting noise online, the answer isn’t found in a blanket rule. It’s found in the woman in front of you and what her body is ready for next.

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