Trimester 1: is really a get to know the changes in your body as your baby grows and avoid exercise that puts excessive strain on you ( more than normal, if you have been training a while you may be aware of some moves which now feel harder )
Essentially this trimester sets you up for the level you can work at in Trimester 2 and 3. The fitter and more active you are now, when you have to take things down a notch as it gets later on in the pregnancy. You’ve done most of the hard work and its more a controlled and safe maintence level of work now to see you through.
Tip: If you are new to exercise as you have become pregnant, do not think of this as your chance to become mega fit for your baby. This will have to wait until after you have given and been given the all clear to exercise again by the Dr. The best thing here to always be in a maintence mode. If your daily steps has always been over 10,000 then there’s no reason why you still can’t aim for this ( maybe with a few more sit downs of course ). If you have barely done a few hundred then edging this up to a couple thousand at most over a slow period of time will be ok but again, listen to your body.