I've been asked this question a lot; "can I still exercise while I am pregnant? The answer is yes! Within reason, Of course consult your doctor first! I highly advise working with a certified trainer with experience training through pregnancies.
-Avoid contact sports
-Monitor heart rate
-Make sure you stay hydrated
-Immediately stop if you feel faint or dizzy.
-Avoid lifting heavy weights (which increases intra-abdominal pressure. Excess intra-abdominal pressure can be a serious matter causing muscle injury or even early labor or bleeding)
-Avoid multi joint exercises. (Low-blood pressure during pregnancy and changes in the hormones which help lubricate your joints)
-During the last trimester:
-Avoid balance exercises (that baby belly will through off your center of balance)
-Avoid any exercises the require you to lie on your back (personally I avoid these during the entire pregnancy with my clients).
Don't let this scare you off though! There are many reason to keep exercising during pregnancy!
Reasons to continue to exercise while being pregnant:
-Detoxifying the body
-Increasing insulin sensitivity
-Increasing energy level and mental clarity
Improving cardiovascular function
-Helping the brain gain better control over the body
-Maintaining appropriate weight gain