Following a few simple rules can see you remain fit and healthy, your baby be safe and secure and you back to enjoying your running and sport once your baby has arrived, advises physio Mark Buckingham.

First trimester

During the first trimester, or three months, on the whole you will be able to train normally. The issues will be any sickness you feel alongside the tiredness of training and developing a baby. There is some evidence that Relaxin is high during this time but in my experience with pregnant athletes their inherent strength seems to make this peak a non-event.

Still care is advised with any lower back and pelvis issues around the end of the trimester. A positive effect of Relaxin though is that it promotes tissue healing so that may be good news for those ongoing niggles.

Many women continue their work and sporting lives as normal in this period. The only real alteration will be that the intensity of building towards a specific event in a few months will not be there. Thus whilst the pressure is less there is much to be gained by working on technique and control work that will sit in the memory bank for the future.

Second trimester

The second trimester is where there will be more noticeable issues of fatigue, weight gain, swollen ankles, and altered core control and position due the developing baby. It is during this period is when you will need to start modifying your training.

The big threat is from events that are explosive and with high impact. Running can be included in this but especially long jump and hurdles or activities involving huge trunk rotation as in high jump, throws or tennis and squash. If you are looking at obstacle events you will need to think about just how much impact is involved on the course.

As the stomach swells the ability to do these movements comfortably will diminish and there are increasing risks of stress on the baby. Clearly this is event/sport specific and whilst some athletes manage to train well through this time it tends to be at an increasingly lower intensity.

Listen to your body

The biggest issue is the mind. A keen athlete who has, notwithstanding injury, always been in control of her body can find these uncontrollable changes tough to take. The mental approach is key to this and you simply have to embrace and accept the change rather than battle it. Pregnancy and its changes are all for the good and the idea that you can fight it or ‘not let it change me’ is frankly dangerous to you and your baby.

The typical woman who runs or plays sport will all experience these feelings and each one will have their own cut off point. There is no right or wrong time to slow or stop activity. It is however vitally important to honestly listen to your own body and not try to make yourself do what you think you ought to. A healthy, sensible approach is something like a very good runner who recently said she had found running had become just too uncomfortable (and slow!) so she stopped – ‘What was the point?’ She could swim and walk fine so that is what she did.

Third trimester

It is the third trimester that the biggest changes occur and during this period it will become clear to you that anything more than easy running, cross training and conditioning work is a risk that is not worth taking. You have to ask the question “why am I doing this? Is it beneficial from a conditioning perspective or is it just training for training’s sake?” When you are just going through the motions then you are doing it because you feel you ought to, not because you are gaining anything. So stop!

The end of third trimester is when the hormone Relaxin, that make the ligaments lax and stretchy to help in the baby’s delivery, really kick in. It is these hormones that pose the biggest risk in long term for you and your body. They make impact work more likely to have a detrimental effect on areas like the feet and especially the pelvis.

The pelvis and low back

The pelvis is held together by three fibrous joints. Relaxin acts to make the fibrous ligaments around these joints stretch during delivery. This loss of pelvis stability leads to pain and with repeated impact makes the sacro-iliac joints more likely to shift and become dysfunctional. Further, the forward tilt of the pelvis due to the baby’s weight makes this shift more likely to happen. With this forward tilt, the lumbar spine is arched to its ‘end of range’ and becomes compressed and painful. Around 1 in 5 ladies will experience low back pain and / or pelvic pain during pregnancy.

There is much that can be done to help it but the avoidance of those activities that cause pain is the first thing to do! Many women will also point to their work and time on their feet as being an issue. The research evidence says that individualised exercise for core strength and stability alongside manual therapy from a physio experienced in pregnant ladies and good adherence to advice has the biggest effect on pain and your ability to function as normal. Over 70% of women found this approach the most useful.

The use of good quality support belts for the pelvis and the bump have also been shown to be effective but they must be more than a stocking.

Feet during pregnancy

Ladies often find that their feet have expanded and flattened due to Relaxin. Use only good supportive trainers and avoid flip flops or sandals throughout your pregnancy and especially the third trimester to keep as much of the integrity of the foot structure as possible.