Walking routine

Before getting pregnant I was going to the gym around 2-3 times a week. I was actually doing the couch to 5k program. I think it’s what helped me conceive. I had been doing that fairly regularly for 2 months.

I have only gained 10 pounds so far this pregnancy but I am starting to feel the aches and pains come on and I’ve read how great walking is for you and how it can help with labor later on. I want to get into a walking routine especially since fall is quickly approaching. I’m thinking of going to the gym to use the treadmill until the weather cools off.

My question is - what’s a good duration to start at? Couple times a week for 20-30 minutes or is that too much? I’m not completely in active now but I will say the only exercise I get is when I’m on my feet at work.