Exercise in pregnancy is a common topic of concern for mums-to-be. There are vast resources of information online but this can be overwhelming and it may be difficult to discern which advice is best to follow.
Some women may feel anxious because the advice they receive from their peers or health care professionals is inconsistent with the information available online and they do not know who or what information to trust.
In this article woman’s health physio, Kim van Deventer, answers common pregnancy exercise related questions.
In this article:
Is exercise safe during pregnancy?
Why is it good to exercise during pregnancy?
How can I make sure that I am exercising safely?
Exercises that are encouraged or should be avoided during pregnancy
When is exercise not safe in pregnancy?
What if I can’t exercise because of other issues?
When and where to get help
One of the first questions I usually get from a new mum-to-be is "What exercise should I be doing now that I am pregnant?".
Once the reality sinks in that she is now responsible for growing a little life inside of her, more questions seem to stream out with anxious desperation. "What should I avoid?", "How much should I be doing?" and "How will I know when I am overdoing things?".
No matter what a pregnant woman’s previous level of activity is, most usually have same concerns about exercise during pregnancy.
So let’s answer a few important questions and put your mind at ease.
Is exercise safe during pregnancy?
Yes, it is. During an uncomplicated pregnancy physical exercise is safe and beneficial for the baby and the mother.
Regular, moderate intensity exercise is encouraged in healthy pregnant women and it is not associated with increased risk of preterm birth.
According to some low quality studies, however, there may be an increased risk for miscarriage when there is intense exercise at the time of implantation and it is advised that if you want to become pregnant you may want to consider limiting the intensity of high-impact exercise in the week after ovulation, and refrain from repetitive heavy lifting in the first trimester.
Why is it good to exercise during pregnancy?
What a relief it is to know that there are so many benefits to exercising during pregnancy that it is too difficult to discuss all of them in detail in one article.
I have summarised a few of the major benefits for mum and baby in the table below.
The above table shows that not only is exercise beneficial for mothers, it is also substantially beneficial for foetal health and well-being which may extend into childhood and adulthood.
The programming effect
Regular exercise during pregnancy seems to elicit what scientists call a "prenatal programming effect". This means that foetuses adapt to an impaired nutrient supply (either under- or over nutrition) by changing their physiology and metabolism in utero.
It has been found that low birth weight is more likely associated with changes in the cardiovascular system whereas a higher than normal birth weight, due to a maternal “obesogenic” environment, is more likely associated with disorders of glucose metabolism such as obesity and diabetes mellitus.
This "programming effect" highlights the importance of managing maternal body composition and dietary balance during pregnancy.
Essentially, what the science says is that if you are fitter and healthier during pregnancy and if you create a healthy environment in utero during the critical time of foetal organ development, your baby will also be fitter and healthier at birth.
Using this time in your life is a good way to make lifestyle changes that stick for you and your child.
How can I make sure that I am exercising safely?
Up until recently women were advised to avoid strenuous aerobic exercise during pregnancy, but new research has shown that most women can continue with their pre-pregnancy exercise routines with no adverse effect.
1. Understand how your body changes
To make sure that you exercise safely during pregnancy it is important to understand the changes that occur in your body during pregnancy and how they affect you and your baby.
Everything from your hormones and connective tissue to your joints and organs will experience phenomenal change.
A few of these changes include:
Your blood volume increases by almost 50% and there is up to 50% increase in your cardiac output (how hard your heart has to work to move all the extra fluid around).
You will have 20% more oxygen consumption and an increased sensitivity to CO2 in your bloodstream.
Your rib cage expands and your diaphragm is pushed up by 4cm.
There is a 30% increase in kidney volume and the length of your kidneys increases by 1 to 1.5 cm.
Your joints loosen, your centre of gravity shifts and your stability is reduced which causes your stance width to increase and your step length to decrease during walking.
In addition to this your baby’s core temperature is approximately 0.6 ˚C more than yours.
It may be a little easier to understand why you swell up, why you feel out of breath, why you need to go to the toilet more often, why you waddle and why you feel like a human furnace most of the time. Even in the snow.
2. Understand the aims of exercise during pregnancy
The aim is to maintain current fitness levels if previously active and to improve fitness levels and develop healthy lifestyle habits if you have not previously been physically active.
Avoid aiming to achieve peak athletic levels during pregnancy. After pregnancy the aim is to regain your previous level of fitness or if you were not previously exercising, to improve on what you have achieved during pregnancy.
3. Training Volume
The UK’s Royal College of Obstetricians and Gynaecologists (RCOG) recommends that women engage in 30 minutes of moderate intensity aerobic activity each day or approximately 210 minutes (3.5 hours) per week.
Studies have shown that doing more than 270 minutes each week could potentially lead to pre-eclampsia in some women.
For previously sedentary pregnant women and recreationally active pregnant women the guidelines for exercising in pregnancy are now almost the same as for non-pregnant women. Get fit slowly and build it up gradually, or maintain it.
4. Monitoring workout intensity
Traditionally, measuring your heart rate during exercise outside of pregnancy is accepted as the most effective way to monitor exertion and gauge exercise intensity levels. However, during pregnancy your heart rate response varies day to day due to the previously highlighted physiological changes and using a heart rate monitor is not as reliable.
You should aim to avoid over-exertion but you do not need to keep your heart rate below any particular number. Instead you should use measures that gauge the intensity of your physical activity using perceived rate of exertion like that of the "Talk Test" or "Borg Scale".
Keep in mind that every pregnant woman will have her own level of perceived exertion. Exercising with a friend is a good way to monitor your intensity. The talk test is a simple and reliable gauge that will help to ensure that you meet your cardiovascular and metabolic demands during exercise when pregnant.
I find the talk test easier and more practical for pregnant ladies to use. If you are able to maintain a conversation while exercising without feeling out of breath or uncomfortable, then you know you are working at the right level.
The Borg Scale is a little tricky to remember each level of intensity if you haven’t used it before and some women have reported that it is also not as easy as the talk test to use on a whim.
In pregnant elite sportswomen there may be a limit to how intensely they should exercise. There is evidence that exercising at intensities above 90% of your maximum heart rate may compromise foetal wellbeing. It is advised that elite athletes, trying to keep within ‘safe’ ranges of exercise intensity, should measure heart rate directly.
5. Temperature Regulation:
Maternal temperatures above 39 degrees Celsius may harm your baby. Make sure that you do not overheat by choosing cooler times of the day to exercise in, staying well hydrated and wearing loose, breathable clothing.
If you exercise in a pool make sure that the temperature of the water is less than 33 degrees Celsius.
6. Risk of falls:
You are more susceptible to injury when you are pregnant so you may need to alter your routine if you usually participate in sports or activities that might pose a risk of injury.
During pregnancy you will experience temporary balance impairments and you should avoid anything that puts you at risk for abdominal and joint injury due to falls. This includes most contact sports, vigorous racquet sports, and exercise involving balance.
7. Progressing exercise:
If you are pregnant with no complications and are new to exercise, start slowly and as low impact as possible and then build it up as you are able. Start with 15 minutes, 3-4 times a week and slowly increase it to 30 minutes every day.
If you are already recreationally active and have no pregnancy complications then you can continue to do what your body is used to. Adjust things as your talk test allows.
If you are healthy and have no pregnancy complications, adding brief higher intensity intervals to your workout will help you burn more energy and enhance your enjoyment of exercise in late pregnancy.
Just remember to keep the intensity below 90% of maximum heart rate.
8. Good to know:
Avoid lying on your back for prolonged periods of time during exercise (especially after 16 weeks) if you have symptoms such as faintness or light-headedness.
Yoga has been shown to be safe and more effective than walking or general antenatal exercises.
Remember that some exercise is better than no exercise so find an exercise you enjoy and stick with it.
Exercises that are encouraged or should be avoided during pregnancy
Many women often ask me for a list of specific exercises that they should be doing or that they should avoid.
In the table below I have listed specific exercises that are encouraged during pregnancy and some of those that are best to be avoided during pregnancy.
*Please note: Exercises should only be done if they are within your capabilities and according to your talk test. Do not start new high impact or higher intensity activities if you are not accustomed to them.
Every day during pregnancy your body is dealing with different changes, so from a fitness and energy perspective your abilities and performance may also change from day to day. Take exercise one day at a time and always listen to your body.
Only do what your body can manage for that day.
When is exercise not safe in pregnancy?
Exercise is not safe if you have:
Vaginal bleeding
Reduced foetal movement
Serious heart, lung, kidney or thyroid disease
Poorly controlled Type1 diabetes
History of miscarriage, premature labour or "small for dates" babies in this or previous pregnancies
High or low blood pressure (discuss with your doctor)
Placenta praevia after 26 weeks (discuss with your doctor)
Acute infectious disease
Seek medical advice before commencing exercise in pregnancy if you have (or are):
Asthma
Controlled Type 1 Diabetes (discuss with your doctor)
History of miscarriage
High blood pressure
Early placenta praevia
Anaemia
Extremely overweight or underweight
Heavy smoker
Pelvic or low back pain
Stop exercising immediately and call your doctor/ midwife as soon as possible if you experience the following:
vaginal bleeding and/or fluid leaking from your vagina
uterine contractions
dizziness
chest pain or uneven heartbeat
headache
severe and abnormal abdominal, calf, back or pelvic joint pain
difficulty in walking
What if I can’t exercise because of other issues?
Pregnancy complications
If you have any pregnancy complications you may be limited in what you are able to do, but there may also be certain types of exercises which are still suitable for you.
Discuss this with your obstetrician and get clarity about what you may and may not do. Once you have this information your physiotherapist can help determine if there is an exercise that is appropriate for you.
Common complaints
During pregnancy there are common physical complaints that you may experience. These can cause barriers to starting exercise or continuing with an existing exercise routine.
Low back and pelvic girdle pain (PGP, SPD etc.) is estimated to affect about 50% of women during pregnancy.
This condition can be debilitating, but it does not have to be that way for you. There is specific advice for you and a few simple exercises that you can do to help yourself become pain free and stay that way.
Pelvic floor dysfunction and urinary incontinence result in many pregnant women avoiding physical activity during pregnancy (and after). If you learn how to correctly activate and strengthen your pelvic floor muscles, you can help prevent these issues or cure them. Having a healthy and responsive pelvic floor can help make labour easier for you too!
When and where to get help
If you have any physical problems during pregnancy the secret is to get help early.
The sooner you are diagnosed the easier it will be to manage and the quicker you can get back to enjoying your pregnancy.
If you are ever unsure of anything and would like to have information about antenatal, postnatal and women’s health and fitness issues then POGP is a great resource.
Physiotherapists, especially those who are specialised in antenatal and postnatal rehabilitation, are able to provide you with the information and guidance that can get you (and keep you) safely exercising and help you manage any of your physical complaints during pregnancy.
In the meantime
Educate yourself, be kind to your body, appreciate it for what it is accomplishing and learn to really listen and respond appropriately.
About the Author
Kim Van Deventer is a freelance healthcare writer and digital content strategist for healthcare businesses and medical content agencies. She worked as a physiotherapist for more than 14 years, specialising in sports injury rehabilitation, chronic pain management, and women's health. Kim combines her clinical experience and digital marketing skills to create relevant and helpful content that improves patients' lives. You can find Kim on LinkedIn
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