Fitness during pregnancy

Laura
I had a million questions for my doctor at my last appointment, but completely spaced to ask about abs exercises during pregnancy. I know crunches aren't good or ones that involve laying on your back but I'm curious if any are safe/helpful for labor and staying healthy during pregnancy? I have continued my workouts from pre pregnancy and plan to continue throughout full term. Just wondered if I could continue some form of core strength or not.  Thanks in advance :)