If in any doubt at all consult your obstetrician. This is especially important if you have complications. Some of the things to discuss include:
- The type of exercise you like to do
- Your general fitness level
- How much exercise you did before you conceived. 
- Your desired intensity level 
- Any complications with your pregnancy
Ultimately – see the conclusion below – especially number 5!
Some general benefits of exercise
- You might actually (shock, horror!) enjoy exercise – or at least the social aspect .
- A more efficient engine means more energy
- Improve your posture  and circulation 
- Improve your cardiovascular health
- Get stronger
- Improve your work capacity (see work capacity below)
- Stronger back muscles – help alleviate back pain as your belly grows 
- Stronger core muscles – help prevent incontinence 
- Relieve stress 
- Improve your sleep and ward off insomnia 
- Ward off pregnancy-induced bone loss 
- Prepare for the physical demands of labour (see work capacity below)
- Improve your recovery after labour 
- Initiate a faster return to pre-pregnancy fitness and weight 
- Increase your ability to cope with the physical demands of motherhood (see work capacity below)
- Overheating has been linked to developmental problems for baby in animal studies
- Lying on your back (from 4 months) can restrict circulation. Modify exercises to on your side.
- Excessive intensity is thought to have effects on birth weight (3rd Trimester), though there is conflicting evidence and opinions, so this is still inconclusive 
- Dizziness or feeling faint
- Heart palpitations
- Chest pain
- Swelling of the face, hands or feet
- Calf pain or swelling
- Vaginal bleeding
- Deep back or pubic pain
- Cramping in the lower abdomen
- Walking difficulties
- An unusual change in your baby’s movements
- Amniotic fluid leakage
- Unusual shortness of breath
- Decreased foetal movements
Pregnancy specific benefits of exercise
|Changes||Cautions (things to be aware of)|
|Increase in body weight||Changes in Balance / Coordination due to increased weight and the distribution of the weight|
|Loosening of all ligaments (Relaxin)||The loosening of ligaments can make you more prone to sprains and other injuries|
|Increase in resting heart rate||Don’t use heart rate to guide intensity as it has increased – use Rate of Perceived Exertion (RPE)|
|Decrease in Blood Pressure (2nd Trimester)||Avoid rapid changes in position due to decreased blood pressure|
|Increase in Blood Volume, Haemoglobin and VO2 Max (First few weeks after birth)||Improved performance!|
|Abdominal separation (painless)||Sit-ups or crunches may worsen this, and are ineffective.|
Things to avoid
Avoid jolts or falls . Unfortunately vigorous or extreme activities such as horse riding, skiing, mountain climbing are out. You should also avoid most contact sports, such as football, basketball and so on. In the later stages of pregnancy, avoid activities that involve jumping, frequent changes of direction and excessive stretching (such as gymnastics).
Limitations of Guidelines
Public health recommendations by their very nature are designed to capture as many members of the public within their umbrella as possible. They are an excellent starting template. They often have current information and links to resources for further inquiry and should not be overlooked.
A great example of sensible pregnancy and exercise recommendations can be found at:
The reason I particularly like these recommendations is their acknowledgement of relative capacity, which is often lacking in Public Health statements.
If you haven’t exercised before becoming pregnant, you would approach the new activity pretty much the same way as if you weren’t pregnant. That is, you’d seek the help of a professional who can design a structured program with your particular goals and needs in mind. Gradual development of strength and fitness with incremental improvement over time.
On the other hand, someone who’s been exercising for years, has built up a baseline of strength, endurance and other general physical skills is going to have greater physical capacity than someone who has not. This woman would be able to do much more than her previously inactive counterpart. Her loads and speed would be reduced compared to pre-pregnancy levels as a margin of safety, but she could still outperform others at her gym of lesser capacity.
Strong abdominal muscles support your spine. The internal core and pelvic floor abdominal muscles act as a natural ‘corset’ to protect the pelvis and lumbar spine.
Your pelvic floor muscles are weakened during pregnancy and during birth (vaginal delivery), so it is extremely important to begin conditioning the pelvic floor muscles from the start of your pregnancy.
Appropriate exercises can be prescribed by a physiotherapist or a personal trainer who has training and experience with pelvic floor. It is important to continue with these throughout your pregnancy and resume as soon as is comfortable after the birth.
Warning signs when exercising during pregnancy 
If you experience any of the following during or after physical activity, stop exercising immediately and see your doctor:
If the exercise you’re doing makes you feel strange or hurts in a non-working-muscle kind of way – stop! The best guide to whether something is working for you or not is how it feels. The rough guide can be summarised as follows:
- Get advice for your particular circumstances
- Every woman is different
- Try things out
- Listen to your body
- You can still work hard but don’t overdo it.
Consider exercise during pregnancy an opportunity for ‘maintenance’ rather than for ‘improving performance’.
Victorian Government Better Health Channel Guidelines:
Sports Medicine Australia FactSheet:
The website babycenter has some useful articles, including:
 Lokey, E. A., Tran, Z. V., Wells, C. L., Myers, B. C., & Tran, A. C. (1991). Effects of physical exercise on pregnancy outcomes: a meta-analytic review. Medicine and science in sports and exercise, 23(11), 1234-1239.
 Nascimento, Simony L.; Surita, Fernanda G.; Cecatti, José G. (2012). Physical exercise during pregnancy: a systematic review. Current Opinion in Obstetrics & Gynecology: December 2012 – Volume 24 – Issue 6 – p 387–394
 Horak, T. A., & Osman, A. (2012). Exercise in pregnancy: review. In Obstetrics and Gynaecology Forum (Vol. 22, No. 4, pp. 13-16). Sabinet Online.
 Hay-Smith J, Mørkved S, Fairbrother KA, Herbison GP. (2008) Pelvic floor muscle training for prevention and treatment of urinary and faecal incontinence in antenatal and postnatal women. Cochrane Database of Systematic Reviews 2008, Issue 4. Art. No.: CD007471. DOI 10.1002/14651858.CD007471.
 Mørkved S, Bø K. (2014) Effect of pelvic floor muscle training during pregnancy and after childbirth on prevention and treatment of urinary incontinence: a systematic review. Br J Sports Med 2014;48:299-310 doi:10.1136/bjsports-2012-091758
 Brandao KL, Mottola MF, Gratton R, Maloni J. (2013) Bone status in activity-restricted pregnant women assessed using calcaneal quantitative ultrasound. Biol Res Nurs. 2013 Apr;15(2):205-12. doi: 10.1177/1099800411423807. Epub 2011 Oct 13.
 Salvesen KÅ, Hem E, Sundgot-Borgen J. (2012) Fetal wellbeing may be compromised during strenuous exercise among pregnant elite athletes. Br J Sports Med. 2012 Mar;46(4):279-83. doi: 10.1136/bjsm.2010.080259. Epub 2011 Mar 10.
 Szymanski LM1, Satin AJ. (2012) Strenuous exercise during pregnancy: is there a limit? Am J Obstet Gynecol. 2012 Sep;207(3):179.e1-6. doi: 10.1016/j.ajog.2012.07.021. Epub 2012 Jul 20.
 Poudevigne MS, O’Connor PJ. (2006) A Review of Physical Activity Patterns in Pregnant Women and Their Relationship to Psychological Health. Sports Medicine – January 2006, Volume 36, Issue 1, pp 19-38
 Kramer MS, McDonald SW. (2006) Aerobic exercise for women during pregnancy. Cochrane Database of Systematic Reviews 2006, Issue 3. Art. No.: CD000180. DOI: 10.1002/14651858.CD000180.pub2.
 Goodwin, A., Astbury, J. and McMeeken, J. (2000), Body image and psychological well-being in pregnancy. A comparison of exercisers and non-exercisers. Australian and New Zealand Journal of Obstetrics and Gynaecology, 40: 442–447. doi: 10.1111/j.1479-828X.2000.tb01178.x