Jenny Blizard looks at how pregnancy affects the musculoskeletal system

This article provides a detailed guide on how pregnancy affects the musculoskeletal system and what you can do to maximise your post-natal recovery in order to enhance and speed up your return to sport.

Pregnancy results in a natural, yet gradual weight gain all over, but obviously most marked in the abdominal area. This causes a change to the centre of gravity and balance, often causing marked changes to the natural curvature of the spine. Along with this, the hormonal influences from six weeks gestation onwards can result in joint laxity, which is normal in pregnant women but can often lead to joint dysfunction and pain. The hormone relaxin is believed to cause an increase in extensibility (length changes) in all ligaments, but most noticeably in the pelvic girdle. Ligaments still exhibit laxity for up to five months after birth and if breastfeeding, throughout the whole of this process and weeks beyond cessation.

Athletes can often return to activity rapidly provided that they look after themselves during the ante-natal period and immediately post-natal.

Functional stability

This is essential for the wide variety of tasks that we perform. It is required to allow enough compression or connection between the bones of our joints so that they don’t fall apart. Several components of our body coordinate to provide this stability. The passive system includes the joints and ligaments, which connect the bones and reinforce and support the joints to prevent them from separating or dislocating. The active system includes all the muscles and tissues that connect the muscles, together known as the myosfascial system.

Contractions of specific muscles work to compress the joint surfaces together, creating stability. We also need the joints to move and this is coordinated by the amazing control system consisting of the brain, nerves and all the receptors that are in your muscles and joints that send information to the brain. This system regulates how much contraction or compression and stability you need and controls the firing and timing of specific muscles. You need stability with mobility. Think of buildings designed to withstand earthquakes – they are built to bend and deform, but re-establish their form after the perturbation. Hence stable, but mobile.

The challenges to this system during pregnancy

The core is likened to a cylinder with the diaphragm at the top, the spine at the rear and the deepest layer of your abdominal muscles, which are the postural stabilising muscles, creating the cylindrical shape. Finally, the pelvic floor forms the bottom. This cylinder works together to ensure effective load transfer during movements such as a stable trunk to allow movement of the arms and legs. During pregnancy the abdominal wall gets stretched with the growing bump, the diaphragm becomes elevated and the pelvic floor has to withstand the extra load. As can be imagined, this is a major change to both the cylinder’s structure and function.

The main function of the cylinder however is respiration and both stability and continence will obviously always be sacrificed for this. We have to breathe – basically, if you don’t breathe properly, your stability and continence mechanisms will never work properly either. It is surprising just how many women neglect this during pregnancy!

In addition, as the weight of the baby changes so does your centre of gravity – you have to re-establish balance and you do this in one of two ways: Either use your mid-spinal extension muscles, which helps to maintain extension in your upper back, or squeeze the rear part of your pelvic floor and gluteal muscles to stabilise through your hips.

The problem arises when these changes and substitution strategies are not kept in check throughout the ante-natal period and balance is re-established in the post-natal period. This has profound implications for you as an athlete.

The abdominal wall and implications in pregnancy

As your abdominal wall stretches in the last trimester of your pregnancy, the midline fascia that connects all of your abdominal muscles at the front comes under significant tension and in a large proportion of women can develop a separation known as “rectus diastasis” in the final stages of pregnancy. The substitution strategies that can develop as a result of this to achieve stability can cause an increase in downward pressure on the contents of your pelvis and have been shown to lead to prolapse and bladder incontinence.

What you need to work on

Providing a detailed ante-natal and post-natal programme is far beyond the scope of this article, but the information provides you with a guide to what happens to your body and what areas you need to work on in your plan. Pilates classes aimed at the pregnant woman will be perfect for you.

Firstly, your breathing pattern will become shallow and the mechanics of how you should breath will be reversed. Simple, regular deep-breathing exercises throughout pregnancy will allow you to continually focus on the correct breathing pattern, which should then become easily re-established post-natally. A deep breath starts in your belly, rises up into your mid chest and then finally opens up your upper chest. During pregnancy this becomes reversed, so the upper chest rises initially.

Maintaining an upright posture by using your spinal extensors will ultimately overload your joints in your upper back – think then post-natally when you no longer have a bump and you will be sat down for repeated periods of time feeding. Upper back pain is very common after pregnancy! Think also that fi xing through these muscles will make the spine rigid, which has implications for trunk rotation during your athletics. Practicing regular trunk rotation exercises as well as the breathing exercises should help maintain good trunk movement.

The other common substitution strategy is using your gluteal muscles and rear pelvic floor muscles to maintain balance and to grip with to effectively hold the pelvis together. This strategy will have implications post-natally for your hip motion. Limitations in hip flexion and rotation will predominantly be aff ected, but for those involved in field events and hurdling, abduction movements (out to the side) will severely affect your technique. Additionally, this strategy, if not released at some point, can ultimately cause groin pain as the structures at the front of the hip are constantly placed under tension. Despite your bump, hip flexion exercises to ensure your glutes do not predominate can still be achieved.

Throughout pregnancy, it is important that you work on your breathing pattern at the same time as working on good abdominal control. This will hopefully prevent the substitution strategies post-natally that we discussed earlier and reduce the potential for a diastasis recti. In terms of your athletic performance, you will be in a much better position to return to sport earlier and your core cylinder should be in a stronger position to start to stabilise again.

Finally we finish at the bottom of the cylinder, which is the pelvic floor.

In a previous article (AW, May 15) by Jean Johnson and Mark Buckingham, the pelvic floor was given attention and there is much more information readily available on the internet, TV, women’s magazines and information from your midwife. It is my experience, however, that for those women who engage in sport in particular, the tendency is not for the pelvic floor to weaken post-natally, but for it to become dysfunctional. Further research is being published currently, which supports this theory and brings about changes to guidelines for assessing and treating this dysfunction.

If you think about the way many muscles respond to trauma, they have a tendency to weaken as well as become contracted. Treatment is provided to strengthen the muscle at the same time as releasing this contracted tissue. Consider also that if you were to fall and cut your knee, with or without stitches, then at fi rst you protect, then gradually as the wound heals you start to bend and straighten the knee. The wound may open a little, but eventually it heals and scar tissue rarely develops because you are using it all of the time.

Now think about the pelvic floor post-natally, for at least a minimum of six weeks you just don’t go there! Despite encouragement to do pelvic floor exercises, the pelvic floor is usually very tender even just to perform basic toileting needs.

So how exactly is it going to heal? In a contracted state of course! Breathing exercises aiming to stretch and drop the pelvic floor on the “in breath” and slowly draw up the pelvic floor on the “out breath” help to prevent dysfunction. It is my opinion that all post-natal women should have their pelvic floor assessed at six weeks, especially those who are athletic or who engage in heavy lifting.

A few final tips

FEEDING POSITIONS

As you will be feeding your baby constantly, use this time to work on your posture. It’s so common to see women slumped in bed or in a chair. If in bed, lie on your side with a pillow under your baby to bring it up to your breast or bottle. This takes the least strain on a tired body and won’t allow further postural imbalances to develop. If sitting, then set yourself up with a feeding chair and stick to it. Use a dining chair, sit upright with a pillow behind if needed and put one or two pillows under your baby to again bring up to you rather than you hold your baby.

Finally, place one or two pillows, or a stool under your feet, to bring your knees up to level with your hips. Just in this position, your postural muscles will be in a position to work again. You can also start to do your breathing and pelvic floor exercises in this position – a perfect opportunity to have time to look after you, when time is short.

CARRYING YOUR BABY

Limit holding your baby on one hip – you will be surprised how many women come to see me with low back pain and hip pain upon commencing running again. Instead, use a long wrap to either cradle your baby in front or on your back.

Changes during pregnancy

Posture changes with increasing weight of the baby
» Stretching of the abdominal wall
» Difficulty taking a full breath
» Rectus diastasis – separation of abdominal wall in last trimester
» Back pain can lead to the postural muscles being inhibited

Impact of labour and delivery and possible areas for trauma
» Pelvic floor
» Abdominal wall
» Pubic symphysis and sacroiliac joints

Summary

It is imperative that to hasten your return to the sport, you look after yourself well in the ante-natal period by attending a class or, if preferred, one-to-one sessions with a qualified women’s health physiotherapist. I would also strongly recommend that you have a post-natal MOT with a good women’s health physiotherapist in order to maximise your recovery and prevent any complications in the future.

» Jenny Blizard is a chartered physiotherapist who specialises in women’s health physiotherapy. Visit blizardphysiotherapy.co.uk or email [email protected]