How do you Modify Ab work?

[Poecat]

I am at 19 weeks, and I know your not supposed to lie on your back after 20 weeks or is it before? Anyway I have heard that some people modify, so I was wondering if anyone had any suggestions.

 

[shopaholic]

I just had my baby. I did standing ab work and also did abs without going down to the floor most of my pregnancy. I found good pregnancy ab work in Gay Gasper's step and strike and easier ab work in Tape fit for 2.