I was 26 weeks when I tried to jog and had gotten a really bad pain in my lower stomach near my belt line, everyone I know ow says pregnant people aren't suppose to run or bend over (instead, squat.) But I guess if you don't have any pains then it won't hurt the baby.
Crunches no!.... If u were running b4 pregnancy then yes continuing to run is fine. Once Ur belly gets bigger invest in a maternity support belt. Do not start running as a new workout wait until after baby. If Ur wanting to stay in shape while prego which is great. B4 my pregnancy I ran 3miles everyday. I stopped in my 1st trimester bcuz I was so sick. I never started running again but would walk the 3miles instead. I also did a prenatal workout DVD (find on Amazon) every other day. Make sure to drink 9+ glasses of water a day. But always check w Ur dr.
Just remember when you work out less oxygen reaches the baby. Your temp goes up and your heart beats faster. Which can be dangerous. Moderation is key
My doctor recommended no excise during the first 3 months, after that depending on your pregnancy and how its going they will let you know what's okay to do or not..
Running is fine, especially if it's something your body is use to before getting pregnant. Just pace yourself and stay hydrated...
Crunches I wouldn't do.. Check out pregnancy workout apps or even on Pinterest a lot of moms post pregnancy workouts for different trimesters :) I'm 35 weeks and still do mini workouts when I don't feel as lazy ;)