Is it possible to tone up while pregnant

HALEY • @bedtime my kids turn in to dehydrated philosophers who need a hug. 😍😘

I am in my 1st trimester and I'm not in great shape but not in horrible shape either, if I stick with a running and light weight bearing exercise program could I tone enough where it would be noticeable or would all that work just fight excessive weight gain?? I would like for my arms and legs to have some definition.