Pregnancy & Exercise (Now there’s two of you)

| 04/06/2012 | 0 Comments More

The following information is copyright.  The reproduction and use of this document must have the consent from its author MIKE BUSS.  When consent to use the content the following acknowledgement must appear clearly at the beginning and end of the document.

‘This work is copyright and has been reproduced with the permission of its author MIKE BUSS MSc (Sport & Exercise Science)’.

Original guidelines for exercising during pregnancy were published in 1985 by theAmericanCollegeof Obstetricians & Gynaecologists (ACOG).  Since then the ACOG have released updated guidelines.  It is important to know that the ACOG did not countermand the original guidelines of 1985 as a result of the update; hence many of the original guidelines of 1985 still stand today.  Encouraging pregnant exercisers to follow guidelines for appropriate frequency, intensity, duration and type of exercise during gestation is crucial for the safety of both the mother and the baby.


Before entering into an exercise regime during pregnancy, you should first be aware of the following;


Exercise during pregnancy is ideal for women who are considered by their doctor to be low risk and who were exercising before pregnancy.  However, pregnancy is not a time to start an exercise regime.  ACOG has published a list of contraindications to exercise, which should be discussed with all pregnant women who wish to exercise.


These Contraindications to exercise during pregnancy can be broken into two categories, these are Absolute & Relative.


Absolute Contraindications (these are conditions where exercise during pregnancy is not recommended).


Statement Yes or No
History of 3 or more spontaneous miscarriages
Ruptured membranes
Premature labour
Diagnosed multiple pregnancies (eg: twins)
Intrauterine growth retardation (baby size smaller than expected)
Incompetent cervix (cervix becomes softer and more open than normal)
Placenta praevia (portion of the placenta sits over cervix making it   vulnerable to detatchment)
Pregnancy-induced hypertension
Venous thrombosis or pulmonary embolism (clots to the legs or lungs)
Known cardiac valve disease
Primary pulmonary hypertension
Maternal heart disease


Relative Contraindications (these are conditions which must be reviewed by an obstetrician or professional in the field of pregnancy prescribed exercise, who will make the decision as to whether exercise should be undertaken).


Statement Yes or No
Thyroid disease
Extremely over or under weight
Extremely sedentary
Breech presentation in third trimester
History of bleeding during pregnancy


Screening during pregnancy:

All pregnant exercisers should be appropriately screened and have their GP’s permission to exercise, preferably in writing.


Further screening questionnaire:

What is your over all activity level?
What are your daily activities? (eg: are you on your feet all day? What type of job do you have? How often do you exercise?)
Sporting Involvement: (sports involving potential to falling and contact sports should stop immediately)
Record of previous injuries (ligament laxity during pregnancy may make the pregnant exerciser susceptible to reinjury, shin pain can become aggravated because of increased weight)

For the regular exerciser it is advised that training should now switch to a maintenance programme to ensure that the risks do not outweigh the benefits.  You can continue to exercise at an appropriate level to your fitness, providing there are no adverse effects, you feel comfortable and do not push yourself.

It must clearly emphasise that you can only maintain minimal tone during pregnancy.  Contraindicated for both mother and baby to attempt to do anything more.

Before starting it is advisable to wear a supportive bra and appropriate footwear, more so than usual, also you shouldn’t exercise on an empty stomach as this may cause glycogen levels to drop too low.


The next section, we will go through the:

  • The benefits of prenatal exercise
  • How pregnancy changes the way you move
  • The down side of exercise, things to avoid and signs of danger
  • Moves for beginning exercisers, advise for advanced exercisers, and simple exercises for all pregnant women
  • Group exercise programmes
  • Recommended relaxation exercises


At the turn of the 20th century, pregnancy was considered an illness.  Upper-class women were ordered to rest in bed until the baby was born.  All physical activity was stopped, and good health was maintained by sitting still.  Things have sure changed! Today pregnant women are encouraged to be active, to exercise, and to keep their bodies strong and healthy.  No pampering for you – it’s off your duff and into your workout clothes!


Why exercise?

Your body is under a lot of strain during pregnancy.  The bones, muscles, joints & organs are all struggling to keep up with the demands of your growing baby.  Your body could sure use some help.  That’s where exercise comes in.  it gives you all the benefits it gives any exerciser, and then some because you’re pregnant.


Some benefits from exercising during pregnancy: 

  • Improves strength
  • Improves blood circulation
  • Reduces fatigue, gives more energy
  • Improved mood and emotional well-being
  • Less weight gain
  • Less swelling of legs, feet, hands & face
  • Relief from constipation
  • Less physical discomfort from achy legs & back
  • Increased strength and stamina to get you through the demands of labour and delivery (the average labour is equal to jogging a half marathon).
  • An easier time getting back into physical shape after delivery

Further benefits from water based exercise:

Compared with the same workload on land, exercise in the water can decrease the mother’s heart rate by up to 10beats per minute and cause fetal heart rate changes to be less marked.  Because water conducts heat 25% faster than air, the woman’s core temperature will not rise as quickly and her fetus will have an extra cushion of protection against overheating.  Because water also decreases the venous pooling effect, helping to reduce the effects of swelling during pregnancy.  The mother’s prone body position (when swimming freestyle and breast stroke) also promotes optimal blood flow to the fetus.  All of these things combine to make water-based exercises one of the best forms of exercise during pregnancy.


For all of these great reasons, this is a great time to get off the couch and exercise!


How pregnancy effects exercise:

Even if you are a seasoned athlete, your body will react differently to exercise when you are pregnant.  Watch for these changes;


  • Balance fail after 20weeks as your abdomen throws you off centre of gravity, making you more susceptible to falls.  This is something to remember if you participate in activities such as jogging or tennis etc.
  • As the growing uterus crowds the lungs, you’ll loose your breath much sooner during exercise.  Working harder for longer wont change this.
  • Your heart naturally works faster during pregnancy, but more blood is channelled to internal organs (such as the uterus) and less to the muscles.  This can make the muscles tire more quickly.
  • The hormone called relaxin, relaxes the pelvic joints in preparation for giving birth, it also loosens all ligaments and joints making you more prone to sprains and falls.


Another thing that can change the way you exercise during pregnancy is increased blood flow and a higher metabolic rate.  This means you’ll feel warmer than usual when you exercise and may become over heated sooner than you would expect.  This can be dangerous.  Some animal studies suggest that overheating can cause birth defects.  To be on the safe side you should take caution against overheating through exercise, especially in the first trimester.  To test yourself, take your temperature by placing a thermometer under your armpit when you finish exercising.  It should not be higher than 101 degrees F.


To keep from over heating:

  • Drink about 16ounces of water or sports drink two hours before you begin      exercising.
  • During exercise, drink 5-12 ounces every 15-20mins.
  • Weigh yourself before and after exercise and drink two more glasses of water for every pound you’ve lost.

You can see that exercise during pregnancy is not the same as before.  Because your body reacts differently to physical exertion, now to be more mindful of how exercise affects not only you, but your baby as well.


The dangers of exercise, things to avoid and signs of danger:


Some activities are just plain dangerous for pregnant women.  Your body is not the same as it was before you were pregnant and it doesn’t react to physical stress the way it used to.  This is especially true of exercise that involves any kind of abdominal trauma.  Avoid jumping, jarring motions, or rapid changes in direction; they may cause joint instability and injury.


Because some kinds of exercise can harm the fetus, I recommend you stay away from:

Scuba diving – decompression may harm the fetus

Skiing – water or down hill skiing risks violent falls and collisions.

Surfing – again risky falls.

Horse back riding – this sport is risky because of severe falls.

Contact sports – such as football, hockey and basketball.

Jogging – this poses risks of over heating and jarring joints.  OK only for seasoned runners until last trimester.


This of course is only a partial list of obvious dangers.  Whatever sport you are considering, use commonsense and talk to a doctor about any sport you’d like to take part in.

Even when you follow all the following do’s & don’ts of safe exercise, you should look out for possible danger signs.  If you have any of the following symptoms while exercising, stop immediately and see your GP.


  • Vaginal bleeding
  • Dizziness or light – headedness
  • Shortness of breath
  • Severe pain (anywhere, especially in the abdominal area)
  • Contractions.


Any of these symptoms may be a sign that you need to slow down, or they might be a danger signal that you need medical attention.  Either way, your GP needs to know that your exercise programme has caused this reaction.  “The No pain No gain” mentality doesn’t cut it during pregnancy.


In the past, pregnant women with diabetes were told not to exercise for fear of disturbing the blood sugar levels that could affect their fetus.  But more recent research has moved many doctors to change their mind.  Mild to moderate exercise for diabetic women appears to have no negative effect on pregnancy and the baby.  Of course, pregnant diabetic women should only exercise with permission and supervision from their GP.

Effects of exercise on the fetus:

Primary considerations are the acute effects of exercise on the fetal temperature, heart rate, and oxygenation as well as its chronic effects on gestation and Birthweight.  Because the mother has greater exercise tolerance than the fetus, any exercise programme should be designed with the wellbeing of the developing baby as the prime consideration.


Fetal temperature:

Overheating of the fetus can have serious effects, particularly in the first trimester, when the incidence of miscarriage is highest and birth defects are most likely to occur.  If the mother overheats during exercise, the fetus will be hotter than the mother because it cannot dissipate heat effectively.  ACOG guidelines state that the maternal core temperature should not exceed 38degrees C.  to avoid overheating, the mother should understand that her core temperature is related to both the intensity and duration of exercise and that it is therefore important to avoid both prolonged and high-intensity exercise.  Recommendations for staying cool include:


  • As stated already – stay well-hydrated.
  • Avoiding exercise outside on hot, humid days.
  • Avoid saunas, steam rooms & Jacuzzi’s.


Do not be lulled into a false security if you’re not sweating during exercise.  Core temperature starts to rise before perspiration occurs.


Blood flow to the baby:

Exercising in the supine position (on back) may also affect blood flow to the baby.  In this position, the enlarging uterus can compress the vena cava (a large vein that carries blood back to the heart), thereby decreasing the amount of blood that returns to the heart and reducing cardiac output.  This can result in a reduction in blood flow to the fetus and to the mothers head, causing dizziness or light-headedness.  The ACOG recommends that no exercise be done in the supine position after week 16.  However, there is evidence that range of movement, low intensity, supine exercises does not adversely affect cardiac output until after week 35.  Best advice is just to stay away supine exercises going into the second trimester.  Never spend more than 2-3mins on your back.


Also never perform rapid or vigorous movements, and always advise her to be aware of the signs of reduced cardiac output such as dizziness or light-headed feeling.  If these occur, she should immediately roll onto her left side and then slowly sit up.


Fetal heart rate:

A change in fetal heart rate suggests that a change has occurred in the fetal environment.  Marked decreases in fetal heart rate in response to exercise may indicate fetal distress (such as a lack of oxygen or over heating).  One study showed that fetal heart rates were normal as long as the exercise intensity stayed moderate (around 140bpm).  However, when intensity increased to an average maternal heart rate of 180bpm, fetal heart rate decreased significantly in 20% of participants.  This drop in fetal heart rate occurred during the first 3mins of the recovery phase and lasted 1-10mins.  The implications of this are:

  • That strenuous exercise above 140bpm should be avoided.
  • The cool down phase of a workout should be gradual, since fetal risk may be greatest immediately after the conditioning bout of a workout.


Birthweight & gestation:

The most marked increase in fetal weight occurs in the third trimester.  Intense exercise at this stage can result in decreased Birthweight and/or a shorter than normal gestation period.  These are not considered healthy birth outcomes.  One study followed pregnant joggers and aerobics participants who attended 3-11 high intensity exercise sessions per week (the average heart rate was 166bpm).  The birthweights were lower in exercising mothers, particularly in the babies of the mothers who continued to exercise more than 4 times per week after week 28.


It’s not known which specific combination of frequency; duration & intensity are likely to cause problems.  Current ACOG guidelines state that exercise intensity should not raise the maternal heart rate above 140bpm and duration should not exceed 40mins with breaks every 10-15mins.


Pregnant exercisers should check with their GP to ensure that maternal weight gain and fetal growth are increasing at a satisfactory rate throughout the pregnancy.  If not, their exercise may need to be curtailed and their nutrition intake assessed.


Maintaining a recommended target heart rate:

Trainers should encourage pregnant exercisers to be realistic about exercising in moderation.  Some women may need to be discouraged from trying to keep up with non-pregnant exercisers or compete with what they were able to do prior to pregnancy.


Pregnant women should be aware on how to measure their heart rate and check it regularly, preferably every 5-10mins.  Alternatively the best way to manage your heart rate is to use a heart rate monitor, which you can check constantly throughout your workout.


Pregnant women should also be aware that their resting heart rate will also be higher during pregnancy, and average resting heart rate of 70bpm could go up to 100bpm during pregnancy.

Effects of exercise on the mother:


Pregnancy-related changes that influence exercise performance:

As the body shape changes during pregnancy, so does the centre of gravity, which affects stability, balance and co-ordination.  Consequently, exercise classes that involve rapid directional changes such as aerobics & circuit training may put the pregnant exerciser at risk of injury.


The hormone relaxin is increased in the body during pregnancy.  This hormone increases joint laxity, which may make the pregnant exerciser more susceptible to injury.  For this reason, stretching should be done very gently.


Exercise-related discomforts:

An important consideration with pregnant exercisers is the amount and type of discomfort they may feel when exercising.

Many experience urinary frequency and incontinence

Breast tenderness

Back pain

General fatigue

Exercises such as press ups, tri-cep dips, and exercises performed in the kneeling position and arm exercises that go across the chest might feel uncomfortable


Whilst the discomforts experienced by pregnant exercisers are usually minor, they merit care and attention to how your body feels and stop if necisary.  You should consult a trainer who specialises in pre/post natal exercise to develop a programme that will minimise your risk of injury or discomfort.


Separation of the rectus abdominus:

Another concern for the pregnant exerciser is the separation of the rectus abdominus at the linea alba (the strip of connective tissue that joins the abdominal muscles in the centre).  This occurs in about 30% of pregnant women who want to continue doing abdominal work should ask their doctor to check for separation between the abdominal muscles at each antenatal visit.

If separation does occur, abdominal exercises should cease.  It is recommended that the muscle be supported or braced by crossing the hands over the abdominal area when doing any crunch-type movement.


Pelvic floor strengthening:

Kegal exercises (those used to strengthen the pelvic floor muscles) should be performed during pregnancy.  There are two ways to increase the strength of the pelvic floor muscles.  One is a long, controlled isometric contraction of these muscles.  The other is a short, hard, contract-release contraction.  Both types of exercises should be done.


Sets of 5-10 contractions performed several times per day should be done.  Strong pelvic floor muscles will recover more quickly and be stronger after delivery and be helpful in preventing urinary incontinence.  Women with serious incontinence problems should be referred to a qualified physiotherapist who specialises in pelvic floor conditioning.


The do’s and don’ts of exercise during pregnancy:

Even safe sports and exercise programmes need to be closely monitored during pregnancy.  This list of do’s & don’ts will help you make informed decisions about your workout routine:



  • Don’t begin a new routine without explicit permission from your GP if you;
  • Have toxaemia
  • Have high blood pressure
  • Have kidney or heart disease
  • Have a history of miscarriage or premature birth
  • Are excessively over weight
  • Have placenta previa or bleeding during pregnancy
  • Have asthma


Don’t over do it.  If an exercise hurts, skip it.  If you feel fatigued, stop.  Don’t push through to exhaustion.  If you cant speak comfortably, you’ve passed the safety point.  Listen to your body and exercise only when it feels good.


After the first trimester, don’t do exercises (such as sit-ups) while lying on your back.  This position causes the weight of the baby to press on a vein leading to the heart.  This can decrease the blood flow to the fetus.


Don’t do exercises that involve excessive stretching.  Your joints and ligaments are going to be lax.



When you begin a prenatal physical fitness programme, there are a few things to keep in mind so that you and your baby get most benefit from your effort.


Talk to your health care provider & your pre/post-natal exercise professional before you begin any exercise regime.  Explain what you’ve done, what you want to do now, and how often you want to exercise.  Together you’ll come up with a programme that gives you all the benefits of exercise without any the risks.


Warm up your muscles before you exercise.  Walk slowly for at least 5mins before you build up your warm up.  (Gradually build up your warm up so that you are fully warmed up for your main activity).


Cool down after your exercise session.  Walk around slowly for at least 5mins until your breathing and heart rate have returned to normal.  Stopping exercise suddenly can cause dizziness, so cool down fully.  Utilise the exercise ball for support during stretching.


Rise slowly.  When you get up from the floor too quickly, you can get dizzy or even faint because your heart is working so hard to pump blood to all your exercised muscles that it may not get a full supply to the brain.  So always rise slowly.


Drink lots of water before, during & after exercising.


Keep cool.  It’s important that you don’t over heat, especially in the first trimester.  Be sure to wear loose clothing and drink plenty of fluids.  Avoid strenuous workouts & outdoors on hot humid days.


Keep up your calorie intake.  Even if the only exercise you get is lifting the TV remote.  You need 300 additional calories to feed your baby each day.  When you are exercising you’ll need more to replace the lost calories.  Do not exercise to lose weight during pregnancy.


Schedule a definitive exercise time each day.  Life is hectic and things that aren’t scheduled don’t get done.  Set aside about 20-30mins at least 3 times per week for exercising.


When to stop exercising:

Finally, make sure that you are aware of the signals to STOP EXERCISE!!! If at any time during an exercise you feel;

  • Very hot
  • Faint
  • Dizzy
  • Short of breath
  • Experience vaginal bleeding
  • Have palpitations
  • Blurred vision
  • Disorientation
  • Severe or continuous headaches
  • Lower abdominal pain
  • Tightness or cramping
  • Back pain
  • Pubic pain


Then STOP IMMEDIATELY and consult your obstetrician.


Exercise during pregnancy:

Exercise during pregnancy can be a very beneficial experience if you are conscious of the precautions to take and knowledgeable about the effects that exercise can have on you and your developing baby.  The guidelinesand limitations for exercise should start as soon as you know you are pregnant or begin trying to become pregnant.


1 Understand the limitations put on exercise frequency, intensity and time are for the benefit of the developing baby, not for the mother.  Normally, the mother can handle exercise   much better than the baby.  Your workout routine should not exceed 40mins and no more than 4 times per week.
2 Avoid over heating.  Your growing baby does not have the same ability to dissipate heat as you do.  Consequently, if you get overheated when you are exercising, the baby may be put at risk.  This is especially true during the first   trimester, when the most important growth, cell reproduction & formation   occurring.  To avoid overheating:a).  Avoid prolonged exercise.  Limit the more strenuous phase of your aerobic exercise to 10-15min intervals.  Give yourself breaks in these intervals to rest and cool-off.b).  Stay well hydrated. Drink plenty on water before, during and after your workout.  Take a water bottle with you, and drink its entire contents by the end of the workout.c).  Do not use sweating as an indicator of how hot you may be getting.  Your core temperature may rise without any accompanying perspiration.d).  Avoid exercising outdoors on hot, humid days. Use fans or make sure the gym you use has air con.

e).  Wear light, loose fitting clothing.  Cotton is best.

f).  Avoid saunas, steam rooms & jaccuzi’s at all times during pregnancy.  Your core temperature may be rising without an associated feeling of being hot.

3 Avoid high intensity exercise.  Studies have indicated that when a mother’s heart rate stays in a   range of approximately 140bpm, the fetus has no abnormal responses.  However, when maternal heart rate averaged 180bpm, indications of fetal distress were present. This strongly suggests that high intensity exercise needs to be avoided.  To keep exercise intensity at a safe level, follow these guidelines:a).  Change from an intermeadiate or advanced aerobics programme to a lighter pace programme.  Your programme will not be geared to getting fit/fitter, your programme should now be a maintanence programme now.  Make sure all your   routine is low-impact & use less vigorous arm movements.b).  Learn how to measure your heart rate, and check it regularly. For a 10sec heart rate check, it should be 23 beats or less.  If it is higher, lower the intensity and re-check in 5mins.  Better still use a heart rate monitor.c).  be realistic about your needs to exercise in moderation.  You do not need to keep up with non-pregnant participants or compete with what you were able to do before pregnancy.d).  Have a prolonged cool-down after your workout.  Stopping exercise   suddenly, or going directly from aerobic exercise to lying on the floor can also have detrimental effects on the fetus. Gradually reduce the intensity and drink plenty of water and make sure you’ve fully cooled down before commencing stretching (which should be done sitting down).
4 Avoid frequent & prolonged exercise after 28 weeks.  Even with moderate exercise more than 4 times per week has been associated with decreased birthweight and gestation duration.  So after 28 weeks it’s advisable to go down to 30mins 3 times per week.
5 An increase in your resting heart rate is a normal response to pregnancy.  If your normal resting heart rate is around 70bpm it can go as high as 100bpm at rest during pregnancy.  This is a completely normal physiological change and should not be taken as a sign that you are becoming less fit.
6 Limit the amount of exercise you are doing on your back, and going into the 2nd trimester, you should stop exercises whilst on your back all together.  Laying on your back   could cause a reduction of blood flow to your heart and head, causing you to feel faint and light headed.  More importantly, the blood flow to the placenta and baby can be decreased.  Limit the amount of time you are on your   back to 2-3mins at any one time.  If you do feel light headed, turn on to your left side and rest.
7 About 30% of women experience a separation of the rectus abdominus during pregnancy.  If this occurs abdominal exercises must stop immediately.  Also when doing abdominal exercises, never come up more than a half sit up position.  If you are going to do abdominal exercises regularly, then your obstretrician should regularly check the separation of your abdominal muscles.
8 Reduce the weight you normally do and stop any exercises that involve raising your arms above your head. Free weights should be avoided especially if you are a beginner or novice.
9 The only form of resistance training that should be done should be low weight – high repetition, emphasising on endurance rather than strength training.
10 Perform Kegal exercises.  These exercises are useful for strengthening the pelvic floor muscles, aiding in your recovery from labour and delivery and helping to avoid stress incontinence.  While seated or laying down, pretend that you are trying to stop yourself from urinating.  The small muscles you are squeezing are   your pelvic floor muscles.  Hold each contraction for 10-15seconds and repeat at least 10 times.  If stress incontinence is a problem for   you, do this several times each day and see a qualified Physio who specialises in pelvic floor conditioning.
11 Wear a good supportive sports bra. This helps to provide support for your enlarging and possibly tender breasts.
12 Avoid rapid changes in direction, as your body shape changes, so does your   centre of gravity which may effect your stability, balance & co-ordination.
13 Be very cautious if you are doing step exercise classes, for the same reason as above.  You may be at risk of injury or falling when stepping.  From the first trimester lower the step to its lowest level, don’t use hand-weights and don’t participate in complicated routines – Keep it simple.
14 PUMP Classes.  These classes should be approached with caution.  If you have not done this class before, then don’t begin whilst pregnant.  Keep the weights low and don’t raise weights above the head.
15 Stretch gently.  The hormone relaxin is increased in your body during pregnancy.  This hormone causes increased joint laxity, which may make you more susceptible to injury.  Be cautious and gentle with your stretching and always be seated when you stretch
16 With exercise, pregnant women sometimes experience low blood sugar levels, resulting in light-headedness or faintness.  A light snack 2hrs prior to exercise should prevent this.  Carry a small carton of fruit juice with you in case this occurs.
17 STOP EXERCISE!!!  If at any time during your exercise session you feel very hot, faint, dizzy, short of breathe, experience vaginal bleeding, have palpitations, blurred vision, disorientation, or severe or continuous headaches.It is also important to stop if you experience lower abdominal pain, tightness or cramping, back pain or pubic pain.It is also important that if you feel any of the above problems, that you contact you obstetrician.

By Mike Buss | Personal Trainer


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Category: Fitness Advice, Pre/Post Natal Exercise

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