Exercise & Pregnancy in Athletes

Woman lifting weights at a gym
December 17th, 2018 0 Comments

Hunter Bennett

New exercise guidelines strongly suggest that women should maintain (or even adopt) an active lifestyle both during and after their pregnancy. Doing so will protect them against having troubles arise during pregnancy. It also assists in the normal growth and development of their baby in the womb.

While these recommendations are completely understandable in normal healthy women, they may not apply to everyone. There are differences for those who undertake extremely high volumes of exercise, such as elite and recreational athletes.

Is fertility compromised in elite and endurance athletes?

Athletes who compete at an elite or recreational level have some notable differences to those individuals who would be categorized as simply ‘healthy’ and exercise moderately. These differences include lower body fat percentages, much higher energy being spent, and seriously increased activity levels.

For the most part, these are good things. Collectively they have a protective effect on heart disease and diabetes. They can have a positive influence on bone mineral density (therefore reducing osteoporosis risk) and can cause large improvements in functional capacity.

Pregnant woman running

But when it comes to the ability to get pregnant, it actually goes the other way. In fact, the combination of these factors typically results in a net loss of energy. This is because the energy demand placed on the athlete will exceed their dietary energy intake.

This negative energy balance has been shown to result in hormonal dysfunction, meaning female athletes are often at a much higher risk of menstrual abnormalities and trouble becoming pregnant (Warren, 2001).

How does fertility differ between elite athletes, recreational athletes, and the general population?

There is a growing body of research suggesting that exercise can be of serious benefit for increasing fertility. The situation is actually a little bit more complex(Hakimi, 2017).

Exercise’s impact on becoming pregnant is determined by the intensity of that activity and by the health status of the person performing that activity.
Regular and more difficult activity performed by women at a ‘normal weight’ or ‘underweight’ in accordance with their BMI can actually disturb ovulation and impact fertility.

Alternatively, regular exercise in women who are classified as either ‘overweight’ or ‘obese’ has been shown to assist in the regulation of the menstrual cycle. Regulating your menstrual cycle assists with ovulation and enhances fertility.

Related Article: Pregnancy & Running By Trimester

Finally, those women who fall into a ‘normal weight’ range and participate in regular exercise at a moderate intensity are unlikely to see any declines in fertility. They will also experience a great number of additional health benefits.

It now makes sense as to why fertility can be negatively impacted by both recreational and elite athletic populations. These two groups are likely to perform a lot of high-intensity physical activity and are also highly likely to have a lower BMI (Evenson, 2016).

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What is the relative energy deficiency in sport (RED-S), and how does it affect fertility?

Considering the above, it is important to note that the seriousness of this interaction is also impacted by an individual’s dietary energy intake. Which all comes down to what is known as their relative energy deficiency in sport (or RED-S, for short). RED-S refers to the impaired physiological functioning caused by a relative energy deficit.

The sort of energy deficit experienced by female athletes during intense training cycles and prolonged periods of competition.

A maintained energy deficit can cause disruption in the body. It can cause impairments in metabolic rate and hormonal profiles, alterations to menstruation, declines in bone health and immune system function, and even reductions in cardiovascular health (Mountjoy, 2018).
In short, it’s not good.

With this in mind, many elite athletes unknowingly sit in a near constant state of RED-S, which has negative impacts on fertility.
With all this in mind, it is often advised that elite athletes who do wish to become pregnant may need to address a number of specific issues – in which they might need to actively increase both their BMI and their body fat percentage (Bø, 2018).

Eating Disorders, Pregnancy, and Athletes

Asking someone to increase both their energy intake and their body fat percentage to increase their likelihood of becoming pregnant is often easier said than done. Optimal fertility age often coincides with peak athletic performance in many individuals.

And given that in many sports, a low body fat percentage is desirable to optimize performance, elite athletes are often forced to prioritize either performance or fertility (Bø, 2018).

This is further impacted if those individuals suffer from an eating disorder – which is not uncommon for people who participate in a sport that requires a low body weight in conjunction with a low body fat percentage (Nazem, 2012).

In this scenario, the hormonal system can become disrupted even further, leading to prolonged alterations in menstrual function and seriously inhibited fertility – which all makes becoming pregnant an even greater challenge.

It is also important to note that pregnant athletes with an eating disorder, and their unborn offspring, are at extreme health risk because they are forced to compete for limited nutritional resources – leading to an increased risk of complications during pregnancy for both mother and child.

It is for this reason that education becomes so important, making sure that everyone has an understanding of how they need to treat their body to achieve the best results in all desired areas.

Do exercise guidelines during pregnancy differ for elite athletes compared to recreational athletes?

Guidelines for physical activity during pregnancy generally encourage pregnant women to adopt an active lifestyle to improve both their health and the health of their baby (Bø, 2016).
However, the focus of these guidelines is for the most part based on healthy pregnant women within the general population. This is the groups who most commonly see a decline in physical activity during their pregnancy.

As a result, there are numerous recreational and elite athletes who often meet and exceed these general guidelines – in which there are actually no clear guidelines established for these individuals.

woman sprinting on a path by the water

Common recommendations suggest that regular exercisers should maintain the same amount of exercise they would normally This may not hold true for more athletic people.  Recent research has clearly demonstrated that most recreational and competitive athletes typically reduce their total training volume during pregnancy.

This also tends to come with associated reductions in exercise intensity (Bø, 2016). Additionally, less than 30% of all athletes will actually continue to run during their third trimester.

This suggests that while most healthy individuals can maintain the same exercise output that they were completing before conception, this may not hold true for more athletic populations. These individuals should reduce training volume and intensity to ensure the safety of their unborn child (Szymanski, 2012).

Related Article: Elite Distance Runners and Breastfeeding: What You Need to Know

Does exercise before and during pregnancy help during childbirth?

There are a number of key benefits associated with exercising throughout the pregnancy period that extend beyond maternal health alone (Hinman, 2015). Maintaining a regular exercise routine has been shown to shorten the duration of labor and reduce the risk of needing a Caesarean section.

Moreover, it can also help ensure a normal birth weight of the child, and help enhance the recovery after giving birth. That you can get back into to exercise faster!

What are the recommendations for athletes and the general population when it comes to returning to exercise?

It is commonly accepted that the physical effects of pregnancy on the human body can last for up to around 4-6 weeks after giving birth (ACOG, 2002).
This means more relaxed ligaments and weaker core muscles. While these don’t sound all that bad, they can increase your risk of joint and muscle injury significantly if you’re not careful.

As a result, it is commonly recommended that during the first six weeks after giving birth you should spend your time performing a moderate-intensity aerobic activity. You can also do some lower level abdominal and glute strengthening exercises. This might mean walking, jogging, or cycling, coupled with exercises such as glute bridges, clams, bird dogs, and side planks (Brumitt, 2009).

During this time period, you should also avoid any high impact exercises that involve any explosive jumping, bounding or sprinting.

Can elite athletes return to exercise sooner?

Many elite athletes have been shown to begin regular training again within the first month of their post-pregnancy period. They can do this without any notable increase in injury risk (Tenforde, 2015). While this might seem odd, there is a good explanation for this.

Elite athletes have a number of years of heavy training under their belt. This means that they are strong, tough, and able to recover quicker. This improves their ability to recover from the physical challenges associated with childbirth.

They typically keep up training throughout their entire pregnancy (although at a lower intensity). It tends to be much easier for them to begin exercise after childbirth. This is why it so important to keep exercising through your pregnancy.

Take Home Message

Exercise is indeed of benefit to an average woman who is trying to get pregnant. When it comes to enhancing becoming pregnant and positively affecting pregnancy-related outcomes, there is a big grey area when it comes to elite and recreational athletes.

In these groups, too much exercise can have some negative effects – which is why education is important. So read, learn, and find what works best for you!


Warren, M. P., and N. E. Perlroth. “The effects of intense exercise on the female reproductive system.” Journal of endocrinology 170.1 (2001): 3-11.

Hakimi, Osnat, and Luiz-Claudio Cameron. “Effect of exercise on ovulation: a systematic review.” Sports Medicine 47.8 (2017): 1555-1567.

Evenson, Kelly R., and Kathryn R. Hesketh. “Studying the Complex Relationships Between Physical Activity and Infertility.” American journal of lifestyle medicine 10.4 (2016): 232-234.
Mountjoy, Margo, et al. “IOC consensus statement on relative energy deficiency in sport (RED-S): 2018 update.” Br J Sports Med 52.11 (2018): 687-697.

Bø, Kari, et al. “Exercise and pregnancy in recreational and elite athletes: 2016/2017 evidence summary from the IOC expert group meeting, Lausanne. Part 5. Recommendations for health professionals and active women.” Br J Sports Med (2018): bjsports-2018.

More References

Nazem, Taraneh Gharib, and Kathryn E. Ackerman. “The female athlete triad.” Sports Health 4.4 (2012): 302-311.
Bø, Kari, et al. “Exercise and pregnancy in recreational and elite athletes: 2016 evidence summary from the IOC expert group meeting, Lausanne. Part 1—exercise in women planning pregnancy and those who are pregnant.” Br J Sports Med 50.10 (2016): 571-589.

Szymanski, Linda M., and Andrew J. Satin. “Strenuous exercise during pregnancy: is there a limit?.” American journal of obstetrics and gynecology 207.3 (2012): 179-e1.
Hinman, Sally K., et al. “Exercise in pregnancy: a clinical review.” Sports health 7.6 (2015): 527-531.

Committee on Obstetric Practice. “ACOG committee opinion. Exercise during pregnancy and the postpartum period. Number 267, January 2002.

American College of Obstetricians and Gynecologists.” International journal of gynaecology and obstetrics. The official organ of the International Federation of Gynaecology and Obstetrics 77.1 (2002): 79.

Brumitt, Jason. “A return to running program for the postpartum client: a case report.” Physiotherapy theory and practice 25.4 (2009): 310-325.

Tenforde, Adam S., et al. “Running habits of competitive runners during pregnancy and breastfeeding.” Sports health 7.2 (2015): 172-176.

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