The questions every runner asks when they fall pregnant?

By Colleen Burns, physiotherapist, founder of PregFit.com.au

Published in the August 2010 Journal of NACE (National Association of Childbirth Educators)

Unlike many of us, for some women, running isn’t simply a matter of begrudgingly pounding out enough kilometers on the treadmill to keep their waistline in check. In fact, for many women, running is a way of life, a part of their identity – and they will assure you that running not only keeps them fit and healthy, but also is fundamental for their own mental and emotional wellbeing. 

When a woman falls pregnant, it is likely that she will have many questions: Am I ready to be a mother? What will pregnancy feel like? What will life be like with a baby? But a woman who loves to run, will have one more burning question: “is it safe to keep running?”

As a physiotherapist, a keen runner, and a recent mum to my first baby – I have a new found understanding of (and respect for) the physical and emotional obstacles associated with running with a bump. I decided to research this topic a little more thoroughly to shed a bit of light on this highly debated topic.

If you’re a dedicated runner - and you’re pregnant – chances are, your husband (and mother-in-law) have already voiced their concern about your intention to keep running. But the fact of the matter is, that the traditional approach to an “unknown risk” is avoidance. And until the last decade, there was very little research into the effects of exercise on the gestational body.  From this lack of scientific research, came a “better to be safe than sorry” approach, and women were advised to rest while they were in this apparently delicate state.

But even though unassuming onlookers will continue to judge the ‘exercising pregnant lady’ as being a little bit selfish (or stupid), most health professionals these days will happily agree that there are many proven benefits of staying active during pregnancy.

But the reality is, that even in today’s society, the idea of running during pregnancy is still highly debated (and not just amongst women and their mother-in-laws) but amongst fitness and health professionals all around the world.

Tiffany Bonasera, a former Australian distance runner and second place getter in the City 2 Surf, is a mother of 2 (aged three and six months). She reported that there was never any chance that she wouldn’t run while pregnant. However, like so many runners, she had a lot of difficulty finding reliable information on the topic.

“To be honest, even my doctors and midwives were not particularly knowledgeable in this area.” Tiffany said

“Though my husband was extremely supportive, I would often get disapproving sideways glances from fellow runners when I was showing, particularly from other women. “

It seems that when it comes to running while pregnant, there are still a lot of misconceptions and hesitations. After speaking with several runners on this topic, there seemed to be some common concerns and questions. I will approach each of these individually:

Will running increase my risk of miscarriage?

The unfortunate fact is, that miscarriage is very common. In fact, around 15 to 20% of all known pregnancies end in miscarriage. But commonly, if an athlete miscarries, this is often followed with ‘guilt by association’.

However, there have been several studies looking at women who continue regular aerobics or running throughout early pregnancy: these studies have found that there was no difference in the rates of miscarriage between the exercisers and their sedentary counterparts.

Will my baby overheat?

It is undeniable that exercise creates a higher maternal body temperature. And there have been studies that have showed some potential risks if a pregnant woman’s core temperature increases too much from the use of a hot tub.

However, under normal circumstances clinical studies prove that during pregnancy, a woman has an improved ability to dissipate heat, and maintain a safe core temperate. This is because a pregnant woman has:

• More efficient sweating response 
• Has increased ventilation (faster/deeper breathing pattern) 
• Has increased blood volume leading to improved heat loss though the skin (hence the ‘pregnant glow’) 

What’s more, these pregnancy-related changes are additive to the exercise-induced changes in the trained athlete. Therefore a pregnant athlete has an even more superior ability to dissipate heat during exercise, ensuring that the foetus is not at an increased risk of ‘overheating’. 

This information suggests that it would be unwise to train at high intensities if you were not exercising at these levels prior to the pregnancy. It would also be unwise to exercise in hot, humid conditions where the thermoregulatory system is compromised.

Will my baby get enough oxygen?

Many years ago scientific research on animals found that during exercise more of our blood volume is directed towards the working muscles thus leading to reduced blood flow to the uterus. This led to a great deal of concern that the baby would have a reduced oxygen supply. However, in more recent years, studies have discovered that women whose bodies are ‘conditioned’ (meaning they were undergoing training prior to the pregnancy) have more than enough blood to go around, and that the foetus is at no increased risk.

When are you not allowed to run during pregnancy?

It must be remembered that there are certain medical conditions that contraindicate exercise during pregnancy. It is wise to be screened by your doctor for any medical pathology that might make exercise during pregnancy ill-advised. 

Some of the conditions that contraindicate exercise during pregnancy include:

• Cardiovascular disease
• Multiple gestation
• Diabetes
• High-blood pressure
• Pre-eclampsia
• Bleeding in the second or third trimester
• Premature rupture of the membranes
• Pre-term labour (or history of pre-term labour)
• Incompetent cervix
• Placenta previa (low-lying placenta)

How hard can I push myself?

You will notice when you are pregnant that you feel ‘puffed’ much more easily. As a result, it is common that you may find your training levels are reduced during pregnancy. Prior to pregnancy, chances are that you would have used your heart rate as an objective indicator of your level of exertion. Due to the cardiovascular changes associated to pregnancy, your heart rate is no longer recommended as a measure of your exercise intensity.

It is now commonly recommended to scale your exercise dependent on how exerted you feel. As it turns out, this is surprisingly reliable. When exercising during pregnancy you can aim to exercise at a level that feels “moderately hard, to hard”. Using the Borg’s Rating of Perceived Exertion (RPE) Scale from 0-20 (0 being no exertion, and 20 being maximal exertion), this should therefore be at a level around 12-15. You should still be able to carry on a conversation.

You'll find that as you baby grows and demands more oxygen, that you will reach this state more quickly. You will need to gradually lower the intensity of your routine to continue to stay within this zone. It's possible, that by your third trimester, that brisk walking will provide plenty of cardiovascular exercise.   

Am I more likely to injure myself?

As your uterus gets heavier, it will place more stress on some of the ligaments in your body. Strain on these ligaments is a common cause of abdominal and back pain during pregnancy. Some runners find that by the third trimester, the bouncing of the uterus while running is too stressful. If this happens to you, switch to brisk fitness walking on a treadmill, an elliptical trainer, stair stepper, or indoor bicycle for your aerobic exercise.

Since pregnancy actually softens all of the body's ligaments in preparation for delivery, your knees and ankles are also at increased risk for injury; at the first sign of joint pain or instability switch to non-impact exercise. Many women love aqua aerobic classes, or lap swimming in the latter stages of pregnancy, as the weight of the baby/uterus floats in the water.

Finally, as a result of your growing abdomen, your centre of gravity and sense of balance is altered, there can be significant changes in your spinal and pelvic alignment, and even something as simple as not being able to see your feet can all predispose you somewhat to injury.  You need to take all these things into consideration when you choose to keep running.  Make sure you run in a safe environment, and be willing to modify your exercise regime if you are finding that your low back or pelvis is getting sore. I would encourage all pregnant women, to combine their aerobic training with suitable strength, core and pelvic floor exercises to help stabilise their joints.

When do I need to stop running?

There are some simple signs to look out for that are telling you that you must stop running. These include:

• Significant fatigue or muscle weakness
• Vaginal bleeding
• Leakage of amniotic fluid
• Dizziness or fainting
• Severe swelling of the ankles, calves, hands or face
• Unusual abdominal pain
• Severe headache
• Vision problems
• Fever
• Elevated heart rate or blood pressure that is not normalizing within 30mins of completing exercise

Will the ‘bouncing’ hurt my baby or cause premature labour?

Although this is a common concern, it would seem that the baby is well cushioned inside the amniotic fluid filled sac in your uterus. There is no scientific evidence linking exercise with foetal injury or preterm birth.

Studies have found that women who continue regular aerobics and/or running throughout their pregnancy area at no higher risk of preterm membrane rupture or premature labour onset.

Interestingly, It has even been suggested that the sound and vibration stimulus may even help improve foetal development, reduce foetal stress during labour and improve their alertness as babies. 

Does it increase my risk of incontinence?

Incontinence is a risk for all women, especially during and after pregnancy/birth. However, I would have to note, that commonly most women who develop incontinence or prolapse are often unfit with poor overall muscle tone and core control.

I would strongly encourage ALL pregnant women (whether running or not) to perform regular pelvic floor exercises. In fact, it is important to learn how to use your pelvic floor together with your deep abdominal muscles and diaphragm to work together as a unit to provide adequate core control. Generally, if one of these muscle groups is not functioning well, then the others won’t be either.

My Conclusion:

If you were not previously a runner, then I would confidently say, now is not the time to take it on. You’re body is not conditioned to cope with the physical demands of running, and it would therefore be unwise to place this unaccustomed stress on your body while pregnant. Having said this, there are definitely other ways to reap the benefits of pregnancy exercise without putting your body under undue physical stress. Some options might include: walking, swimming, stationary cycling, yoga or other monitored prenatal exercise classes.

If the thought of not running during your pregnancy makes you feel sick to the stomach (and it’s definitely not just the morning sickness) then don’t be afraid to discuss your options with your treating midwife or doctor. Check that you do not have any pregnancy complications that are contraindicated to exercise. If you have a healthy, uncomplicated pregnancy, then you have no reason to be scared of running. However, keep in mind that now is not the time to break records. For the next few months you are running for your sanity, not for competition. Be assured, that by maintaining a moderate level of fitness during your pregnancy that your postnatal return to running will be much quicker and smoother. And finally, be sensible, listen to your body, it will tell you when it’s time to pull back. Know the signs and symptoms to watch for, so you know if you need to stop. If you take an educated approach to your pregnancy running regime, along with the right attitude, then you will find you have a safe, enjoyable, healthy and rewarding pregnancy.