Running during pregnancy

Dr. Annie Padgett on running while pregnant

I am 34-weeks pregnant this week and I’ve decided to stop running. I’m not sure it had become much of a run anyway, more a slow plod interspersed with a rather wishful waddle here and there when it all got a bit uncomfortable. I always find it a difficult psychological to stop the running portion of a pregnancy; not getting into my sports kit, timing myself, donning my heart rate monitor and completing the days designated session.

This will be baby number 4 for me, so I’ve jotted a few thoughts down to guide ladies who may not have navigated running in pregnancy previously, on what to expect. I'm also a GP with a special interest in women’s health and lifestyle medicine, so I will also include some tips I’ve learnt along the way, mixed in with my professional opinion.

What to expect

With all things pregnancy and childbirth (and children for that matter), we have to expect the unexpected. Everyone, and every pregnancy is different. What your running buddy did in her pregnancy will not necessarily fit for you, and equally what you did in your last pregnancy might not exactly model this one. As runners, we are used to listening to our bodies, whether that be to ease down or gear up our training load, or knowing whether to push that bit more in the middle of a race. Running in pregnancy really puts those skills to the test.

Generally, we can expect to slow down during the course of our pregnancy, and niggles, aches and issues may crop up along the way to steer us to alter our training. It’s important to listen to these cues to avoid harm to both yourself and your baby, and to avoid unnecessary discomfort and stress for you.

There are physical and psychological hurdles whether you decide to run or stop running during your pregnancy. But there are also numerous benefits to keeping active and fit during your pregnancy.

My key message? Avoid adding anything new to your training regime during your pregnancy. If you previously only did 5k maximum, do not suddenly try out 10k. If you never did any strength and conditioning at all, do not suddenly start weightlifting. Most importantly, listen to your body. If something does not feel right, stop.

First trimester: negotiating the nausea and fighting the fatigue

The first trimester, for many women, brings with it nausea and/or vomiting and an overwhelming fatigue. Running can help with the fatigue to a degree, but when it trots its merry way into your life, you still can be baffled at just how tired you feel. If you're super lucky, you will not have any nausea at all. That’s not been my luck, and there have been many times when I’ve had to turn around on a run because I am retching into the bushes. This is commonly experienced anywhere from 6-20 weeks, but for most people it peaks at 8 weeks and tends to peter out at the end of the first trimester (12 weeks). Good riddance!

The impact this can have on your running is very dependent on your symptoms, what you can eat to mitigate the nausea – as hunger can worsen it – and your training schedule. Eating small amounts of blander foods, more often, can help you keep up with some semblance of normal training over this period, if you feel you are able.

Tips and guidance

The important thing throughout pregnancy, but especially in the first trimester, is to avoid overheating. Heat stress should be avoided. Temperature regulation in pregnancy is even more dependent on hydration and environment and therefore it is important to adapt with this. Keep drinking water and run at the cooler times of day to stave off overheating.

Second trimester: the golden stage

During the second trimester (12-28 weeks) there is the biggest period of growth of your baby, and this can mean you adapting your running intensity and length throughout the trimester. Mentally the first trimester can often cause frustration if you are dogged by nausea, but otherwise feel well enough to train, and the second trimester for many can be a sweet respite from this. The fatigue usually lifts, people around you are now more aware you are pregnant and are supportive, and you are not too huge or uncomfortable yet. All adding up to the best trimester, in my humble opinion. That said, I've found a range of symptoms can cause niggles in the second trimester, and adapting your training load or run length to accommodate this is crucial.

Tips and guidance

The increasing weight of the baby may cause you to feel like you need to pee constantly, especially while you run. Shortness of breath during exercise may increase, as well as your inability to tolerate anaerobic exercise.

During pregnancy your blood volume, cardiac output and breathing increase, and there is less resistance in the circulation. Our body, heart and lungs are processing more blood, and it’s going to more places than ever before. This leads to a slight lag between our constant work and the oxygen available, limiting the ability to really push ourselves on a sprint or threshold session.

Aches and pains may occur in the pelvis, due to the hormone relaxin being released during pregnancy to prepare our pelvis to widen and allow our little one to squeeze down the birth canal on their birthday. Great news for the big day, but in the meantime, it can mean the joints become laxer and a bit achier up till then, which can increase the risk of injury. Jerky movements should be avoided, and running on loose ground or in new footwear at this time might be a bad idea.

The other problem often encountered during the second trimester is keeping your balance, as your centre of gravity changes. This can increase your risk of falling. It’s sensible to avoid running in places where balance might prove an issue normally, such as running on the beach or in muddy terrain.

Third trimester: where time slows down

Running in the third trimester is a labour of love. As runners, we are often quite psychologically attached, some say obsessed, with our running. It’s part of our routine, our escape from the stresses of the day, our refreshment, and our mood boost. Not being able to run when we want to can prove a mental struggle. It’s normal to feel frustrated or annoyed at times, or jealous of your training partners completing races without you. You might feel anxious to keep your fitness up, or just a little out of kilter, not being able to bust out those hard, fast miles as you did previously. And that’s okay. In reality, you will not be as behind as you think when you lace up those running shoes again post-pregnancy.

It’s also rewarding to keep a general semblance of routine despite a scale down in training load, which might mean swapping a run for a swim, but at the same time of the day, or going out for a walk instead of a run on the same route as usual. This all helps keep you feeling motivated and still exercising, even if you feel running might be too much.

In my pregnancies I’ve generally switched to walking and swimming around the start of the third trimester. I’ve managed to run a little longer in this pregnancy, just going with what I felt was right by my body. You will find your personal balance, and some women run right up to the end, others stop much earlier. Whatever you feel is okay.

Tips and guidance

You may find that running triggers more practice or ‘Braxton Hicks’ contractions, more muscle aches, or more heartburn. Your gait may change as your pelvis widens causing your running to feel less smooth and more jolted. All these fun and games can make you consider adapting your exercise regime and phasing your running down. It's completely a personal choice, and whatever you decide is right for you.

If you do decide to keep running, be sure to allow yourself enough recovery time between runs as you’re likely to feel more fatigued as you near the end of your pregnancy. Continue listening to your body and respecting it first and foremost – it’s about to do a momentous job!

Racing

As racing is sometimes not that dissimilar from a hard training session, again there is no hard and fast rule. If you feel you can race, depending on the stage of the pregnancy, then do not let anyone tell you any different – provided you’re listening to your body, keeping hydrated, avoiding overheating and generally easing up if you feel that you’re pushing it too hard.

Be sensible. I won a 10km at 6-weeks pregnant, but fortunately I was not experiencing any symptoms at that point and had done a few park runs. But , I’ve hung up my racing shoes for my pregnancies, and it does no harm for future fitness. You are unlikely to be smashing personal bests at this point, so my advice, especially further on in pregnancy, would be to save that drama for post-pregnancy. And your little one can cheer you on!

The science

Keeping physically active during pregnancy has numerous benefits. Nowadays, we’re living in a society where a lack of physical activity is the 4th leading risk factor for early mortality worldwide, and it has never been more important to promote the benefits of exercise. There is no evidence that physical activity (and running if you’ve previously run regularly) causes any risk to the mother or baby, in healthy, uncomplicated pregnancies. There are very few conditions that running or exercising generally should be avoided in pregnancy, and checking with your doctor or midwife, should be able to clear this up. Some key scenarios where running in pregnancy is best avoided are:

• when you feel you need to stop
• vaginal bleeding
• abdominal pain
• shortness of breath prior to exercise
• chest pain
• headache
• dizziness
• calf pain/redness/swelling
• muscle weakness causing a disruption in balance
• amniotic fluid leakage (‘waters breaking’)
• regular painful contractions.

General benefits of exercise in pregnancy include a reduction in:

• risk of gestational diabetes
• perceived effort and length of labour
• risk of pre-eclampsia
• risk of pre-term birth and low birth weight
• chance of caesarean (and increased chance of vaginal birth)
• length of post-partum recovery
• constipation
• back pain.

Exercise in pregnancy supports healthy weight gain, strengthens the heart and blood vessels, and can help with weight loss after the baby is born. Women who stay active while pregnant often experience higher self esteem, improved mood, better sleep, and a reduced risk of depression. Regular exercise also helps maintain healthy blood pressure, boosts fitness, improves muscle tone, and prepares the body for the physical demands of labour.

There is no increased risk of miscarriage, low birth weight or early delivery. The benefits are just too well evidenced, and disadvantages for healthy pregnancies so sparse.

How much exercise should I do in pregnancy? How intensely can I run?

The American College of Obstetricians and Gynaecologists generally support a guidance of 150 minutes of moderate activity per week. It’s recommended this is spread over the course of the week. The RCOG (Royal College of Obstetricians and Gynaecologists) in the UK, also supports this guidance. As runners who train regularly, it’s likely we will meet this guidance, but we may be doing more vigorous activity than moderate activity.

The evidence shows that this is safe in pregnancy (if previously undertaken) in the first and second trimester. There is less evidence for training vigorously, particularly in athletes who are training at heart rates >90% baseline, in the third trimester, and some evidence of lower birth weight. There does not seem to be any foetal growth restriction in this case, but evidence is lacking.

What if I cannot run?

There are some conditions- usually identified by your midwife or obstetrician (ask if you are not sure), that might preclude running in pregnancy. This can include some heart conditions, pre-eclampsia and premature rupture of membranes among a few others. Do not despair though, this is only a short time period and only a few months of your life. You will get back your fitness after the birth and it’s better you and your baby are healthy and well. Your healthcare professional should be able to give you specific advice on what you can and cannot do.

Post-partum running

Often when women ask for advice about exercising after giving birth, they are given set timings and rules trotted out to them and the next women after them. They often expect to be told what they can safely do when, but this entirely misses the point. No two women are the same, had the same pre-pregnancy fitness, knowledge, pregnancy, birth, or aspirations. People are not machines, that need to power down for ‘x’ amount of time, reboot and when they were not allowed to run one day, suddenly come out of their 6-week check, ready to stand at the start line of their next 5k.

So, what are we meant to do?

Yes, you’ve guessed it...listen to your body. There is no medical reason why you cannot exercise, in some capacity, as soon as you feel able to after the birth, as long as you have an awareness of the changes to expect. The most important point is to focus on strength and conditioning first and foremost, gently moving to running alongside as you feel more secure and supported in your frame.

Things to keep in mind:

1. Your pelvic floor will need some work. Engage in pelvic floor exercises as soon as possible after birth to start working on that strength.
2. Your core muscles need to be eased back in slowly, to avoid injury. Avoid leaping into running straight away and build up with gentle yoga/Pilates exercises and slow core work.
3. The hormone relaxin will likely be in your system still for up to a year, be aware your joints may be more lax, especially around the pelvis, increasing your risk of injury. Build training up slowly, factor in frequent rest days and slowly build up length of your runs to mitigate the risk.
4. Expect a few niggles and aches, particularly in the back, pelvis and core when you start running, and pick up on them as signs of areas to rest or work on. Focus on conditioning your body to withstand the entry back into training.
5. You are likely to feel thirstier, especially if breastfeeding. Ensure you keep hydrated when training.
6. Don’t forget posture and running style. After the changes of pregnancy, lack of sleep and holding a baby on one hip half the time, there can be changes to your posture. Really focus when running or exercising, on your position and adapt and work on this accordingly, seeking advice from a physiotherapist if needed.

Refreshingly, although there is no clear guidance from UK professional bodies, the American College of Obstetricians and Gynaecologists, helpfully supports the opinion that every woman is different and there is no one size fits all guidance template for resuming exercise after pregnancy.

This is liberating, as we are free to rehabilitate our bodies back to ‘normal’ from whenever we feel ready to do so. We should all be empowered as parents to stand up for what is right for our children, and similarly we should also be filled with confidence that we are the ones best placed to decide what is right for our bodies as we ease back into our world of running.

Happy running! And wishing you an excellent pregnancy.

Dr. Annie Padgett

(BM. BMedSc. MRCGP. DRCOG. DipBSLM. Dip ClinDerm)

General definitions for exercise intensity: (not heart rate related)

• Moderate: Quicker breathing but not out of breath. Can hold a conversation but not sing.
• Vigorous: Deep and rapid breathing. Can only say a few words before pausing for breath.

Footnotes

1. Physical activity and pregnancy. (2017). Royal College of Obstetricians and Gynaecologists.
2. Physical activity and exercise during pregnancy and the postpartum period. (2020). The American College of Obstetricians and Gynaecologists- Committee opinion.
3. Kirkby, R. Birmingham, R. (1996). Exercise in pregnancy: Psychological Benefits’. Australian Journal of Primary Health.
4. Exercise after pregnancy. (2019). American College of Obstetricians and Gynaecologists.
5. Running in pregnancy. (2018). Tommy’s.