Exercise and/or running (really, any form of safe, moderately strenuous activity) through your entire pregnancy IS possible. I do suggest one thing– get in relatively decent shape BEFORE you get pregnant.
I have always been active. I began playing soccer at the ripe age of three in the YMCA league back in IL. At first you would have never guessed soccer was my calling fore I could not, for the life of me, get through a game without sitting down in the middle of the field and crying for my parents. Eventually I got over the, heaven forbid, 15 foot separation anxiety and went on to play on an elite club team, then in high school and later at a DI college. Since I graduated in 2010, I’ve stuck to my washed up soccer game in adult leagues, running, lifting once or twice a week, an iStroll workout and occasionally I’ll throw in a fitness class or two.
The week(ish) before I became pregnant (yes, I know the date. We military call them deployment babies 🙊) a friend and I ran a half marathon in Jacksonville, FL. At the time, I was simply strong and healthy– nothing elite. The average Jane can do it. I was not in the best shape of my life fore I definitely peaked in my college years but I am routinely active!
Last thing: The term, “in shape” is very relative. You do NOT have to have a banging 6 pack, be less than 20% body fat or be able to run a 5 minute mile. You DO need to have a daily routine that gets you sweating and pushing yourself out of your comfort zone. Pregnancy should not be your cue to start running/working out! Wanting to be healthy pre-baby, should.