Anatomy of pregnancy and birth - abdominal muscles
- Your abdominal (tummy) muscles are the group of muscles found in the front of your torso.
- Your abdominal muscles give you core stability, help you to move and help deliver your baby during a vaginal birth.
- During pregnancy, your growing baby can stretch and weaken your abdominal muscles.
- Exercising and strengthening your abdominal muscles during and after pregnancy can help them return to their original shape after your baby is born.
What are the abdominal muscles?
The abdominal muscles are the muscles in the front of your torso (or trunk), between your ribs and pelvis.
There are several different abdominal muscles:
- the external oblique muscles
- the internal oblique muscles
- the rectus abdominis muscles
- the transversus abdominis muscles
The most obvious physical sign of pregnancy — your growing tummy or ‘baby bump’ — can affect your abdominal muscles. Strengthening your abdominal muscles during and after pregnancy helps these muscles work as they should.
What do my abdominal muscles do?
Your abdominal muscles are designed to support your torso and give you core stability.
The abdominal muscles come in pairs (one on either side of your torso), and work together to:
- stabilise your torso
- support your spine
- support movements between the rib cage and the pelvis
- allow your torso to twist
- help with functions such as breathing, coughing and opening your bowels
- hold your internal organs in place
During a vaginal birth, you use your abdominal muscles to help deliver your baby.
What happens to my abdominal muscles during pregnancy?
During pregnancy, your growing baby stretches your abdominal muscles. Your abdominal muscles stretch as your uterus (womb) expands with the pregnancy. Your abdominal muscles may weaken because of this stretching.
Sometimes during pregnancy, the two bands of the rectus abdominis muscle (that normally meet in the middle of the abdomen) separate. This condition is called 'diastasis recti abdominus' or abdominal separation.
This can happen due to:
- stretching and weakening of your muscles due to your enlarging uterus
- pregnancy hormones
- weight gain
Abdominal separation may cause pain in your lower back. It might become hard to lift things or do other physical activities.
If you have abdominal muscle separation, your doctor will usually refer you to a specialist physiotherapist. They will recommend a special exercise program. Occasionally, surgery is recommended for this condition.
If you think you may have abdominal separation, see your doctor or maternal health service.
How can my abdominal muscles be strengthened?
Exercising and strengthening your abdominal muscles during and after pregnancy can help them return to their original shape after your baby is born.
A safe way to work your abdominal muscles and improve core strength is by drawing in the muscles without moving your spine. To do this exercise try to imagine sucking your belly button in towards your spine.
Sit-ups and crunches are not recommended during pregnancy. This is for 2 reasons.
- Your stretched abdominal muscles do not work in the same way as when you aren’t pregnant. This makes sit-ups less effective during pregnancy.
- Sit-ups and crunches are usually done while lying on your back, and this position isn’t recommended during pregnancy. Lying on your back during pregnancy can cause dizziness because the weight of your baby rests on your major blood vessels.
Pregnancy-specific exercise classes, such as yoga and Pilates classes can help build and maintain your core strength.
Speak to a maternal child health nurse
Call Pregnancy, Birth and Baby to speak to a maternal child health nurse on 1800 882 436 or video call. Available 7am to midnight (AET), 7 days a week.
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Last reviewed: January 2023