As someone who is admittedly new to the scene but has still drawn breastpreg, the best advice I can give is "draw giant breasts and you can add the kicks later if you'd like."
Usually I have a special layer for the kicks (i draw with paint.net), and, unlike majority of the other parts of the draw itself, it's never designed to be symmetrical in any way, shape, or form. It really emphasizes the kicks compared to the rest of the symmetry in my draws IMO.
Also, note that, when there's no visible activity, or at least no visible kicks, you might as well be drawing hyper breasts. Proper tutorials for those already exist out there, so I won't hammer that in for you.
But hey, you imply that I would complain about that stuff too.~ ;3