Can you run when you’re pregnant?

By Alice Williams

If you google ‘Can Pregnant Women Run?‘ you will get 89,200,000 results, none of those results will be a clear ‘Yes’ or a ‘No’. I know this because that’s what I did 33 weeks ago when I found out that I was pregnant…

The official information available is a mix of low volume studies, caveats and assumptions that are confusing at best, and at worst terrifying – the question turns from ‘Can Pregnant Women Run?‘ to ‘Should Pregnant Women Run’? after 38 weeks of running while pregnant, and many runs later, my answer is ‘Yes’ but there was a long list of questions that I wouldn’t know the answer to unless I had decided to find out for myself.

Running while you’re pregnant, is an interesting mix of physical depletion and mental determination. Normally, the more you do something the better you get at it – If you run pregnant, you will only get slower, you will get heavier, it will only get harder, and there’s nothing you can do to stop this – you have to go into it accepting that your fitness will fall off a cliff. What I found is that the ‘cliff’ had several levels along the way, it wasn’t simply a case of ‘this is how you’ll feel in the 1st, 2nd, and 3rd Trimester’ but clusters of weeks would feel similar and then I would go down another level. For the purpose of this blog post I’ll talk about each cluster.


Weeks 1-5 

Marathon Training, Exhaustion and a Surprise!

I had started training for the Dublin Marathon and had just gotten into doing longer runs. During my second long run (18 miles) I felt really tired like I wanted to cry with exhaustion after only 3 miles, I wrote it off as getting back into training after a couple months of lower volume mileage. I continued with marathon training and did a couple of short races (10km and team mile relay), my results were slower than expected, but both races were in extremely hot weather so I wasn’t concerned. By what was unknowingly my 4th week of pregnancy, my breathing felt off and I struggled on a couple of easy runs – women usually feel a bit off right before their monthly cycle, but this felt worse than normal – I was concerned that I might have an iron deficiency and decided that I should visit my GP for some blood tests. I bought a pregnancy test, so I could be sure to rule out the inevitable question that most women get at the GP when they have a health concern, turns out it wasn’t an iron deficiency…just a baby!


Weeks 5-9 

Minefield of Information, How do I make sure the baby’s healthy?

Anyone who’s been pregnant before will know that it’s an extremely confusing time, and ‘trusty google’ is visited several times a day with a litany of answers (the list of cheeses that you can and can’t eat alone is exhaustive!), tie that in with trying to find out what exercise is safe makes things feel impossible. The articles that I found had conflicting intensity volumes, healthy heart rate bpm ranges, and how many hours a week you can ‘safely’ exercise. I dug a little deeper and came across some blog posts from women that had run throughout their pregnancies at a decent volume and most importantly were positive, and had given birth to healthy babies.

The uneducated concern of a women exercising when pregnant is ‘will exercise restrict oxygen and blood to the baby?’ ‘Does it cause pre-term labour’? ‘Will the baby have a low birth weight?’ and the biggest fear of all ‘Can it cause a miscarriage’? most of the articles I found backed up that exercise is beneficial for the Baby and Mother but what I didn’t get was a definitive answer to ‘How much is too much’? And ‘What can I safely do?’. I realised that no one could tell me this and I had to rely on my own judgement.

At this point, my routine was running six days a week that included Intervals, Tempo, a mid-week hilly club run and a long run. I decided to reduce my long runs to the 14-15 mile range, with the intensity reduced during interval and tempo sessions – going by feel rather than pushing myself as hard as I could.

Although plenty of women do run full marathons pregnant, I decided that it wasn’t something that I wanted to do and I would defer my Dublin Marathon place to 2018. I did however, feel comfortable going ahead with the Half Marathon that I had planned to do in what would now be my 2nd Trimester. Finally, my next concern was nutrition, a woman who’s a healthy weight should gain 25-35 lbs while pregnant, I had to make sure that with regular exercise I was still on track for the baby being healthy and gaining enough weight throughout my pregnancy. I spoke to my Dad who’s a doctor, and he suggested keeping a very close track of my weight and make a concentrated effort to eat enough snacks between meals. I found an online ‘pregnancy weight calculator’ which helped me keep my weight gain on track, and increased calories when I was struggling to gain.

My weekly mileage during this time was around 45 miles. Cardiac capacity during pregnancy is halved, and blood volume doubles, so the effort was noticeable. I was happy to continue with this level of running and although paces had begun to drop, they weren’t significant at this point.


Weeks 9-14

Racing during Pregnancy, Scans, and sharing the news!

At the 12 week scan, the baby was healthy – growing well and very active! It really helped give me piece of mind that what I was doing was healthy for me and the baby.

I ran two races during this time period, my office run club ‘LGN 5km’ and the ‘Ealing Half Marathon’. The 5km race was during my 10th week of pregnancy, and I ended up running 20min51s – I wasn’t at the point of telling colleagues that I was pregnant yet, so made an excuse of being ‘stuck behind some slow guys’ during the congested race to explain my time being slower than the year before. For Ealing, I was 14 weeks pregnant and I thought around 1hr35mins would be realistic and not pushing my body too hard. I started off behind the 1hr35min pacers, but found that the pace felt too aggressive so I held back. Surprisingly, it became the first half marathon that I managed a successful negative split and I was able to comfortably catch up during the second half to finish in 1hr35mins. The race actually felt really enjoyable, and having the knowledge that the baby was healthy at this point helped me relax.

After the 12 week scan I was free to tell people outside my family, in laws and close friends that my husband and I were expecting. Obviously people were happy for me, but it was the start of the first waves of ‘you’ll have to give up running now’ which became a bit of an overwhelming theme throughout my pregnancy. As it turns out, people have very defined views of what you can and can’t do in pregnancy which would soon become very clear to me.

My weekly mileage during this time stayed at 45 miles, with long runs at 13-14 miles. My pace on ‘harder efforts’ had to drop a level and I relied on the feeling of effort to make sure that I wasn’t pushing too hard.


Weeks 15-20 

Leg cramps, back pain, Tena Ladies, and one last Half Marathon

This is when things started to get interesting, blood flow during pregnancy rightly favours the baby – which meant that my leg muscles started acting up. I would get random ‘dead leg’ cramps when I was running, I usually stopped and stretched a bit but mostly these would go away within the first 2 miles. Another factor was lower back pain, my expanding tummy was putting pressure on my lower back which started bothering me – not every run, and it actually hurt more after I sat at my desk for long periods of time, rather than when I was active. Lastly, bathroom breaks – with additional blood flow going to your kidneys during pregnancy you produce more urine than normal, combine that with a baby sitting on your bladder while your body bounces and you’ve got a problem… I had to run mainly in parks that would allow me easy access to toilets, but I hated the feeling that I could wet myself at any moment. One evening, I was running near my house and took an extra detour to round off 7 miles when it happened – I full on wet myself like a toddler!! Thankfully it was dark, raining and I was wearing black leggings!

I didn’t know what to do at this point, would I have to completely stop running for the fear of being caught out again? You can do all the pelvic floor exercises you like, but this was always going to be an issue. Around the same time, my friend suggested we run an upcoming Half Marathon in Richmond, so she could try for a PB by the end of the year and I could run one last Half before I’d have to reduce my long runs further. The problem was that the race was put on by a small organisation and there would be no port-a-loos on route, this is when I came up with a slightly crazy idea – Tena ladies. As you might know from the glamourous TV ads, `Tena Ladies’ are slightly thicker maxi pads that ‘women of a certain age’ wear for bladder incontinence. I decided if I wore one, I wouldn’t have to worry about the lack of toilets situation – on the day, the race was even more disorganised than we thought it would be and the start point port-a-loos hadn’t even arrived! This meant that during the first couple of miles people were weaving in and out to the bushes to ‘relieve themselves’, I should have packed extra Tena Ladies to give out!

Besides the unfortunate toilet situation, the race itself was ok. I had a loose goal time of 1hr40mins, but the mud and the cobble paths made my footing uneven and the lower back pain set in. I ended up finishing in 1hr42mins, and felt like that was a decent effort for 5 months pregnant. Most importantly, my friend improved her Half time by 3.5 mins, she celebrated with Prosecco, I had sparkling water…

My weekly mileage during this time was 40+ miles, again paces to match effort had to be reduced and long runs were around 12 miles.


Weeks 20-25

Stop now or keep going?, 20 week Scan, What should a pregnant woman’s body look like?

20 weeks was really the first hurdle in deciding what I could still reasonably run, my body felt less comfortable running – my stride had shortened significantly, the leg cramps continued, and I was getting bored of the constant bathroom breaks. Little did I know that this would be the first of many times I thought I was doing my ‘Last Run’, yes it would continue to be more difficult, but every time I wanted to quit I got used to the ‘new normal’ and adjusted to what I could do at that point, not comparing myself to what I could do a few weeks previously.

The 20 week pregnancy scan or ‘Anomaly Scan’ looks for any abnormalities in the baby and tracks the baby’s growth, the second part of the scan checks for any signs of pre-term labour or a low lying placenta. I knew going into the scan that if there were any growth issues or risk of pre-term labour, I would need to stop my routine immediately. I think they should rename the 20 week scan, the ‘Scary Scan’ anyone who’s been pregnant will know the anxiety going into the room hoping that everything’s ok with the baby. Thankfully the results showed a healthy baby boy that was already above average weight and thriving – I ended up in the scan a lot longer than expected because he was so active, later on, after doing my continuous ‘running in pregnancy’ research I found out that the mother’s activity levels in pregnancy positively affect the baby and the baby was more active because of me!

At this time, I would get a lot of comments about my ‘size’. I’m generally a very slim person and didn’t really start showing until 5 months, well-meaning colleagues and friends would comment on how ‘tiny’ I was. My own insecurities made me feel like I being judged for not being bigger, and I was paranoid that people thought my running routine was preventing me from looking ‘more pregnant’. I felt like I had to be defensive and tell people exactly how much weight I had gained, and that my baby was actually above average weight. When I look back at this, I realise it was silly to think that this was real judgement, but it also made me more aware that we should never comment on a woman’s size during pregnancy.

I still continued my Wednesday night runs with my club ‘Dulwich Runners’, the club members were incredibly supportive when I told them that I was expecting and the women that had babies gave some great advice about running in pregnancy, as well as being patient with me when I fell behind and took longer on the hills. The club runs are usually about 8-10 miles on what seems like the hilliest route in south London anyone can find. Before I was pregnant I would run a very steady pace on these nights, but I had to reduce my pace significantly – when I was frustrated with struggling, one club member reminded me that ‘there’s no glory in a good Wednesday night run!’. I did eventually have to cut these runs out, after one evening my back pain got very severe on a particularly steep route, and because the route was a large loop I had to jog back in significant pain to the clubhouse. I was annoyed that I had pushed myself too far, and decided from then on to only run in areas that I could stop running and walk back if I ran into trouble and avoid steep hills.

My weekly mileage during this time was 35 miles, however as my paces had dropped, Steve recommended changing to ‘time based’ runs rather than relying on mileage. This meant whatever I could cover in ‘x’ minutes would determine how long the run would be. This approach really helped to make sure I wasn’t pushing the pace on days I felt off and helped me ease slowly into runs.


Weeks 26-30

Relaxing, Losing anonymity as a runner, Ending the year on a high

I expected the 3rd trimester to be physically the most challenging, running wise this started at week 26. My balance felt more off, and thanks to the hormone ‘Relaxin’ my joints felt looser and I found that besides dialling down the pace again, I had to really concentrate on my form – making sure I was as upright as possible and trying not to run on too many uneven surfaces. At this point, I also looked very pregnant so there was a real lack of anonymity when I went running. I found that the general public’s reactions to a pregnant woman running are very mixed – sometimes I would get a wave or a thumbs up, other times it would be a rude comment – one man driving by actually honked his horn and angrily shaked his fist at me! (Pretty extreme), but I tried not to let it bother me and accepted that I couldn’t control people’s views.

Despite being pregnant for half the year, 2017 was my highest mileage ever. I should probably caveat that before Dec 2014, I had never run further than 4 miles in my life – but I’m still counting the small accomplishment!

My weekly mileage during this time was 30-35, continuing with time based runs, and long runs were around 10-11 miles.


Weeks 31-33

No more ‘workout runs’ and one last race

After 32 weeks, I felt another drop in ability and my legs were really struggling to ‘repair’ between runs. This meant that I would need to drop interval and tempo workouts completely to avoid injury and I continued running all my runs at an easy pace with one ‘aerobic’ paced run a week.

I had signed up to the ‘Cancer Research Winter Run’ 10km a few months previously, I wasn’t sure I would be still running at this point but thought I’d enter just in case. On the day I felt a bit self-conscious about being in a race while being quite heavily pregnant – but the race volunteers were really friendly and made me feel comfortable during the bag drop/warmup (one even let me know that she was a midwife, just in case!). I had no idea what pace I was capable of at this point, I predicted about 8min/mile – I went out conservatively based on feel and surprised myself by getting into a rhythm and running a decent second half – finishing in 47min23s.

My weekly mileage during this time was 25-30, long runs were around 9-10 miles.


Weeks 34-36


Most of the pregnancy running blogs that I came across mentioned that week 35/36 was a real turning point, again running would get harder and it’s a point when you have to consider if you want to continue running, or move on to a more low impact routine. I like the freedom in just grabbing my shoes and going for a run outside, and even though I was plodding along, I felt the increased energy I got after going for a run was worth it. Week 36 was ‘snowmaggedon’ in London, so ended up running less than planned – there’s no way a heavily pregnant woman can stay upright in slippery conditions!

My weekly mileage during this time was 20-25 miles, long runs were around 8-9 miles.


Weeks 37 – ??

Waiting for the baby…

‘Full Term’ is between 37-42 weeks, I’m going into my 38 week of pregnancy still running. I have no idea when my last pregnancy run will be, but 1,350 pregnancy miles later I’m happy with what my body has accomplished and any fears or worries I had, have vanished. I’m looking forward to meeting my baby and the next challenge of Post-natal fitness!

My weekly mileage now is 20 miles, long runs are TBC..


After 38 weeks of running throughout my pregnancy, I’m a firm believer that as long as a women has no underlining medical conditions preventing her from running, and continues to get medical clear from midwives/doctors that running throughout pregnancy can only be a positive thing. Yes, there are days of extreme frustration, exhaustion and doubt but it’s also incredibly rewarding to see how strong your body is during all the changes in pregnancy.


Finally, here are the ‘Top 5’ most important things I learned from running in pregnancy….

  1. A sense of humour is key – whether it’s joking with friends about the ‘Tena Lady situation’, the fact that my running form now is a cross between a slow T-rex and a new-born fawn, or that I now I only fit into the man size freebie shirts from races, it’s important to just laugh about it – all this stuff is just temporary and getting out there in any shape is important.
  2. Don’t fall for the comparison trap – There’s no point in comparing yourself to the level of fitness you used to have, and especially important not to compare what you’re doing to what others are posting on Strava and Instagram. I think this is not just true in pregnancy, but for any runner who’s coming back from injury or illness – all you can do is work with what’s currently possible, and have faith that the fitness will come back in time.
  3. Ignore the ‘noise’ – you may come across some judgement about running whilst pregnant, but unless the advice comes from a medical professional, it’s best to ignore it and be comfortable with your lifestyle choice. It’s equally important to be thankful, and listen to the people who are supportive to help you continue.
  4. Stopping isn’t quitting – sometimes I had to stop for a minute or two just to compose myself or walk for a bit, other times I had to cut runs short or not go out for planned runs because I felt awful, pregnancy is unpredictable, you may feel bad one day and perfectly fine the next day – it’s important to not let these days make you feel like you’re failing.
  5. Health– I didn’t have any morning sickness during my pregnancy, or even a cold – I have no evidence that this is due to running but I think pregnancy symptoms were significantly reduced based on my activity level. Mentally, pregnancy hormones can make you feel like a crazy person – I found that running really helped regulate my ‘moods’ and mentally made me feel tougher.


Keep InformedSign up to our Mailing List

If you’d like to receive our highly rated in-depth monthly newsletter – please fill in your details below;

Sign Up Now
Read More
The importance of setting milestones
Read More
The Olympics
Read More
Read More
Running is about community
Read More
Achieving another marathon personal best – arbitrary goals
Read More