Hey guys ,
Im actually almost finished my study to be a Personal Trainer, I would advise NO RUNNING, this does cause your heartrate to rise and more blood to be pumped around your body, this causing your body temp to also rise. After about 15-18 weeks if you are still jogging i would stop that also just due to the fact again of what i stated above as well as the extra pressure that it will be putting on you.
Also do NO ab work, no crunches, no sit ups etc at any time of the pregnancy. If you do any weights make sure they are light and do not lay on your back as this restricts blood flow to both you and the baby.
Safe exercises would be walking - if u want to step it up make it so its powerwalking just so you can still hold a conversation.
Swimming is great as well, just with this make sure again you dont overheat your body.
Pilates for pregnancy is great as well.
Step classes can be ok depending on the levels that you are at. But do check this first as everyone is different.
You can do calf/glute/leg exercises on the mats, as long as you are laying on your side, as well as resistance training again must be laying on you side.
Try to always stretch to cool down as it helps with birth if your muscles are a bit flexible.
With weights, i would avoid going heavy thats its causing a strain on your body, maybe keep it lighter and do more reps. Again this comes down to what you were previously able to do.
Anything that causes you to be unbalanced causes you a high risk of falling so this should be avoided as well.
Make sure during your exercise you have got plenty of fluids on hand just in case and a snack food ( fruit etc ) for afterwards.
All of the above is going with what i have found out from my studies, my doctors and midwifes as well as other personal trainers.
Hope it helped.