Is it safe to do sit-ups in pregnancy?

In a nutshell?

Yes. And no. Well, it's complicated!

Initially you can do sit-ups, but then they’re off-limits

“You can carry on working your tummy muscles doing sit-up style exercises up to around 16 weeks," advises Lucie Brand, personal trainer and founder of bump2mumfitness.com. But Brand says that if you begin to feel uncomfortable before this point when doing sit-ups, you should stop.

Why do people actually do sit-ups anyway?

The benefit of sit-ups (also sometimes called abdominal crunches) is that they help maintain the strength in the top surface layer of your stomach muscles, known as your rectus abdominis.

And why do you need to stop after 16 weeks of pregnancy?

“As it's these surface abdominal muscles that are going to be lengthened and stretched by your growing baby in later pregnancy, there is little point to doing this sort of exercise after 16 weeks,” says Brand.

Additionally, for some people, over-exercising the rectus abdominis muscles in pregnancy puts too much pressure on the abdominal wall, causing a gap to form in between the two sections of your tummy muscles. This condition is known as diastasis recti or abdominal separation. It can happen in the later part of your pregnancy, or following childbirth.

Maria Behenna, founder of FitMama.com, explains that diastasis recti can cause problems with recovery following your labour. “It has been linked with pelvic dysfunction, and can lead to lower back ache and other related painful ailments,” she says.

Don’t lie flat on your back

Another reason to steer clear of the crunches, particularly after 16 weeks, is that from this point it is recommended that you do not lie flat on your back. If you’re pregnant and have tried it, you may have discovered it can make you dizzy. Lying on your back in the later stages of pregnancy causes your uterus to press on a major blood vessel called the vena cava, risking reduced blood flow to your brain and your baby.

But don’t totally ignore those stomach muscles...

Behenna says that when it comes to giving birth, your stomach muscles have a very important job to do. “Your stomach muscles are crucial to pushing your baby out,” she says.

So, while Behenna advises bypassing sit-ups throughout your whole pregnancy, she emphasises that this shouldn’t mean ignoring your stomach muscles altogether. You just need to use other exercises instead.

“There are many safe alternatives to sit-ups which you can do to aid your tummy tone and preparation for delivery,” she says.

Keep your stomach muscles strong – without sit-ups!

Here’s the good news. Brand says that it's entirely possible to keep your stomach muscles strong during pregnancy - even without doing sit-ups.

“We have lots of different abdominal muscles and while the surface ones will lengthen and stretch and maybe even separate as our bumps grow, we can still work on the deep abs (sometime called the 'core'), which will be supporting your bump,” she explains.

“It is a really good idea to keep your abdominals strong during pregnancy as having a strong core will help protect your back, support your bump and may even help during labour. Working your core also involves using your pelvic floor, which is another set of muscles that should be exercised regularly. Most importantly for some, keeping your abs strong and fit during pregnancy will mean a quicker recovery after the birth and an easier journey back to a flat tummy.”

So how can I exercise my stomach muscles safely?

The stomach muscle that you need to focus on working in pregnancy is called the TVA (transversus abdominis), Brand explains. “This is the deepest abdominal muscle, which you can think of as the body’s own internal corset. A strong TVA is the key to being able to have a flat tummy after you have had your baby,” she says.

You can activate your TVA simply by breathing in deeply and letting your chest expand then as you exhale, pulling in your tummy all the way round, as if you are wearing a corset.

Hold it in for a couple of seconds, then release. Make sure that as you do so, you can still breathe deeply and slowly.

“Simple pull-ins like this, and other core strengthening exercises are perfectly safe during pregnancy and will not harm your baby.

“You should try and work your core and your pelvic floor every day (and no one will know you're doing it!) Aim for 50-100 tummy pull-ins and 50-100 pelvic floor squeezes every day,” Brand advises.

Any other alternatives to sit-ups?

Yep - the Standing Pelvic Tilt is a brilliant stomach muscle exercise and safe to dothroughout pregnancy. It’s essential for creating strength through the pelvic floor, but also helps you to practise shortening your long tummy muscles in preparation for pushing out your baby.

First of all, stand with your spine against the wall, feet no wider than your pelvis. Then inhale. As you exhale, tilt your pelvis away from the wall. As you tilt, tighten up the pelvic floor, too. Then inhale and return to the start point. Repeat as many times as you feel comfortable with.

What else can I do to keep my stomach muscles strong through pregnancy?

Brand says the following are crucial to keeping your tummy muscles fit and strong, giving you the best chance of getting your belly back in good shape after you've had your baby:

• Do your core pull-in exercises regularly (see above)
• Avoid excess weight gain, which will stretch the muscles even more
• Take regular moderate cardiovascular exercise. The National Institute for Care and Excellence (NICE) recommends at least 30 minutes per day of moderate intensity activity during pregnancy

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