Although the positive effects of running during pregnancy have been widely documented, there is still understandable anxiety about the relationship between running and miscarriage. A common misconception is that running can cause a woman to miscarry. And women are unsure of how soon to wait after miscarriage before running again.
Losing a pregnancy is heart-breaking for all involved. We spoke to the NHS and The Miscarriage Association whilst writing this article and would advise those who need help and guidance to use both sources as well as guidance from charity Tommy's.
What does the NHS say about running during pregnancy?
The general NHS guidelines when it comes to running during pregnancy are to “keep up your daily physical activity or exercise for as long as you feel comfortable”. It has been proven in numerous studies that running during pregnancy is not dangerous for you or your baby and actually has a number of positive effects.
One study claims running during pregnancy does not lead to lower birthweight or premature birth and further research found it can actually reduce the duration of labour. Exercise during pregnancy helps to prevent gestational diabetes, pre-eclampsia and excessive weight gain, while decreasing the risk of postnatal depression by 25%. It also improves a mother’s cardiovascular fitness and sleep quality, while research in Clinical Medical Insights: Women's Health demonstrates it reduces the risk of chronic disease for the baby, too.
That said, the general advice is to not take up running during pregnancy if you are not already a runner. Women with complications such as severe pre-eclampsia or pre-existing heart disease are not recommended to undertake moderate to intense activity. And women with relative contraindications such as gestational hypertension or mild cardiovascular disease may need to reduce their running duration or volume.
But for non-complicated pregnancies the key message is ‘don't bump, the bump’ and listen to your body as pregnancy progresses. The Active Pregnancy Foundation, which provides guidelines based on the latest scientific research, says women with uncomplicated pregnancies can keep running if they are already a runner. And it doesn't have to be low intensity running as long as you stay properly hydrated.
The World Health Organisation which reviewed the evidence on vigorous activity during pregnancy in 2020, concluded it was safe to continue running at this intensity, but it was not advised as a new activity.
How strenuous a run feels will vary dramatically based on your own general level of fitness and how often you ran before you were pregnant, so listen to your body and check with your maternity team if you are worried. It is also worth noting that many medical professionals advise women to be more careful depending on their pregnancy history, or if they have any medical problems or symptoms.
Can running cause a miscarriage?
We spoke to Ruth Bender Atik, National Director at The Miscarriage Association about the relationship between running and miscarriage, and what we know so far.
When asked about pregnancy and miscarriage, Ruth explains: “The question whether exercise – and especially running – increases miscarriage risk is difficult to answer. What we do know is that it is very difficult to shift a pregnancy that’s doing well – think of the things women used to do to try to induce an abortion. It may well be, however, that running might accelerate the process of a miscarriage that is already inevitable.”
As Ruth explains, running will not cause a miscarriage to happen, but instead the two are linked in that if a miscarriage is sadly inevitable, the run could be one factor that may accelerate the process. Baby loss charity Tommy’s estimate that “1 in 4 pregnancies end in loss during pregnancy or birth” and are leading ground-breaking research into fully understanding why. It is important to remember, whether you are a runner or not, your body is designed to handle more than a run, but sometimes a pregnancy will not work out through no fault of your own.
Until recently research in this field has been limited but a leading systematic review published in the British Journal of Sports Medicine in 2019 found no increased odds of miscarriage, stillbirth or newborn death in women who were active during pregnancy. It also found no association between exercise volume, intensity or frequency and the odds of fetal mortality. This review analysed 46 studies the majority of which examined the impact of moderate intensity exercise up to 60 minutes long.
"We didn't see that exercise increases the risk of miscarriage. So unless there is a specific medical reason or you're engaging in really, really high intensity, long duration activity, there is not really a particular reason to be adopting your activity levels. And in the case of high intensity, long duration, we just don't know a lot so we recommend speaking to your healthcare provider," says review co-author Dr Margie Davenport, director of the program for pregnancy and postpartum health.
Davenport also conducted a systematic review of 91 studies looking at the effects of prenatal exercise on fetal heart rate and umbilical blood flow. This also found prenatal exercise did not adversely impact fetal heart rate or uteroplacental blood flow metrics.
Sadly the stats show that almost half of women stop running during pregnancy, with many citing anxiety, nervousness or fear of miscarriage as the reasons, according to a 2022 survey published in the Journal of Women's Health Physical Therapy. And it can have a long term health impact. A study published in the International Journal of Basic Sciences and Applied Research found women with miscarriage experience were more likely to be inactive and overweight than those who had not experience miscarriage.
I’ve had a miscarriage, when can I run again?
When it comes to taking up running again post loss, the professional advice is to do as much, or as little, as your body feels comfortable with. Ruth explains: “The physical process of miscarriage and its duration can vary hugely, partly depending on the stage at which you miscarry and also on whether it is a natural, spontaneous loss or one involving medical or surgical treatment.
“Recovery times vary too, especially after surgery or considerable blood loss; and hormonal changes also play a significant part. I’m not sure there is any more sound advice to give than to ‘do as much as you feel comfortable with’ post miscarriage.”
Related: Meet the man running 2000 miles in memory of his son
How running helped my mental health post miscarriage
For some women, returning to running after miscarriage is an important part of their recovery. The boost running can have on an individual’s mental health has been widely documented, and for keen runners, a gentle jog can be hugely beneficial.
One woman who has shared her own story of running and miscarriage is Nat, who blogs under the name ‘This Vet Runs’. We spoke to Nat after reading her blog post on returning to running and she told Runner’s World: “I think if I’d known when it happened initially how common it was, I would have been less quick to assume that I must have done something wrong.
“Running and exercise have been so important to me in my recovery – exercise is always empowering, but when you feel like your body has let you down so much, that feeling of reclaiming ownership of it, and actually feeling pride and joy in what you can achieve is even more huge.”
In her blog post Nat writes: “When I suffered a miscarriage just before I was meant to be running my first marathon, one of my biggest questions was when can I run again. I felt like I was drowning in insurmountable emotions, my hormones were all over the place, and my brain would not allow me to think about anything else even for a second. I knew how much running would help.
“The advice from the doctors regarding exercise was vague, and I’ve learnt that this is probably because people’s experiences post-miscarriage, and post-surgery, are very variable. I was told around 2-3 weeks for running, and that I could bleed for up to 6.”
Nat writes about her gentle return to running over a few weeks, walking and cycling first, listening to her body as she went: “The running felt strange. I was very weak through my core and I didn’t feel the same runner as a few weeks ago, when I’d been ready to take on a marathon. But I did it. 38 minutes. But it was a baseline, and I had no ill effects or increased bleeding.”
At the end of the post she writes: “Overall, I’d say you cannot do anything but listen to your body initially. That is the priority. Mine let me know when I’d overdone it- I had worse pain and worse bleeding afterwards, even if it felt comfortable during.
“The biggest thing is that you absolutely have to adjust your expectations of yourself. If I compared every run to my runs before I’d have got seriously depressed. And sometimes I did. But I have to kick myself. I’m just glad I can get out there and do it again comfortable.”
If you need any further advice on anything to do with miscarriage, contact the Miscarriage Support Helpline on 01924 200799, or Tommy’s pregnancy helpline, run by midwives Monday to Friday 9am-5pm on 0800 014 7800.
