In years past, women were told to limit running while pregnant due to presumed risks of preterm birth. Physical activity during pregnancy was theoretically related to preterm birth due to the release of catecholamines, especially norepinephrine, which might stimulate myometrial activity. Yet, exercise may reduce the risk of preterm birth due to decreased oxidative stress (Berghella, 2016).
What is a preterm baby?
The World Health Organization (WHO) defines preterm birth as babies born alive before 37 weeks of pregnancy are completed. There are subcategories of preterm birth, based on gestational stage: extremely preterm (less than 28 weeks), very preterm (28 to 32 weeks), and moderate to late preterm (32 to 37 weeks) (WHO, 2018). Preterm babies can suffer lifelong effects such as cerebral palsy, severe cognitive impairments, visual and hearing impairments, and poor health and growth.
What’s recently changed?
Research indicates that significant numbers of non-pregnant women and pregnant women are unsure if it was safe for regular runners to continue to run while pregnant. The impact of recreational running during pregnancy outcome remains controversial. However, current research indicates whether running affects gestational age at delivery and birthweight.
Related Article: Baby On Board? – Aerobic Exercise During Pregnancy
What the research says –
Berghella et al. (2016) set out to evaluate the effects of exercise during pregnancy on the risk of preterm birth. The study consisted of 2059 pregnant women who were all before 23 weeks pregnant and were randomized into an aerobic exercise group or in a control group. The exercise group participated in 35-90 minutes of aerobic activity 3-4 times per week.
In terms of birth experience for women between groups, both groups had a similar incidence in preterm births and a similar mean gestational age at delivery. Women in the exercise group had a significantly higher incidence of vaginal delivery and a significantly lower incidence of caesarian delivery.
Berghella et al. (2016) proved that pregnant women with a normal weight, running for 35-90 minutes 3-4 times per week could be safely performed. Exercise during pregnancy is not associated with an increased risk of preterm birth or with a reduction in mean gestational age at delivery.
Similarly, Harmon et al. (2018) found that, in women who ran before pregnancy, the continuation of running during pregnancy does not affect birth weight or gestational age, regardless of mean weekly distance or stage of pregnancy. Both Harmon et al. (2018), and Berghella et al. (2016) found that assisted vaginal delivery rates were higher in women who ran, versus the control of women who did not. Women who ran during their pregnancy also experienced a significantly lower incidence of caesarian delivery. The reason for this possibly may be due to increased pelvic floor muscle tone from running and exercising. Finally, women who ran during their pregnancy experienced a significantly lower incidence of the hypertensive disorder. The findings from both of these studies indicate that running while pregnant should be considered and encouraged, especially for women who were runners before pregnancy.
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In the wake of current research, the Vice President for Education at the Royal College of Obstetricians and Gynecologists (RCOG) recommends that all women take part in regular exercise during pregnancy.
Running while pregnant can:
- Help to reduce fatigue
- Help to ease lower back pain; swelling of the ankles
- Decrease feelings of stress, anxiety, and depression
- Reduce the risk of gestational diabetes and preeclampsia (pregnancy-induced high blood pressure)
- Help improve your baby’s brain development
- Help you get through labor (it will not put you into labor)
- Initiate a quicker recovery post-birth
Related Article: Postnatal Core Exercises
Tips for pregnant runners:
- Wear supportive athletic clothing (proper running shoes and running bra)
- Focus on proper running technique instead of a fast pace
- Don’t run to exhaustion / overexert yourself
- Be aware of unusual symptoms
- You may start sweating earlier and faster, so be sure to adequately hydrate
- Slow down and take long walk breaks as needed, and take recovery days as needed, as this is not the time to push and overexert yourself
- To ensure that your heart rate does not exceed 140 bpm (which would be an unhealthy heart rate for you and your baby), pregnant women use the talk test as a gauge in energy expenditure. The talk test ensures that the entire time you are running you should able to carry on a conversation. If you are unable to talk, stop and take time to catch your breath
Exercises to build strength during pregnancy:
- The Kegel Exercise– Breathe normally as you tighten your pelvic floor muscles for 10 seconds, and relax them for 10 seconds. Perform three sets of 10 repetitions a day.
- V-Sit Roll Back (with medicine ball) – Bring your legs up to a 45-degree bend; lean back slightly. Keeping the back straight, rotate the shoulders, bringing medicine ball from side to side.
- Band Pulls – Grasp a resistance band with both hands and hold it in front of you at shoulder level. Stand tall with your feet shoulder-width apart. Pull your arms out to your sides, then reverse the movement
- Other exercises can be safely performed during pregnancy, such as swimming, indoor stationary cycling (in a calm environment, not an aggressive spin class), brisk walking for pregnant women of all shapes, sizes, and fitness levels
- If complications in pregnancy arise, such as bleeding, preeclampsia, or having multiples, running may not be recommended to you during pregnancy
Berghella, V., Di Mascio, D., Magro-Malosso, E., Marhefka, G., & Saccone, G. (2016).
“Exercise during pregnancy in normal-weight women and risk of preterm birth: a
systematic review and meta-analysis of randomized controlled trials.” American
Journal of Obstetrics and Gynecology, 215 (5), 561-571.
Harmon, M., Hezelgrave, N., Kuhrt, K., Seed, P., & Shennan H. (2018). “Is recreational
running associated with earlier delivery and lower birth weight in women who continue
to run during pregnancy? An international retrospective cohort study of
running habits of 1293 female runners during pregnancy.” BMJ Open Sport &
Exercise Medicine, 4, 1.
Royal College of Obstetricians and Gynecologists. (2018). Online. Available: