This pose is excellent for opening hips.
Sit relaxed with your back as tall as possible. Put base of your feet together. This position should help you open hips and pelvis which is very important for the birth.
Lean back slightly and put your hands behind you and focus on releasing the energy through your pelvis.
You can also bend forward, but do not push yourself too far because of the size of your stomach. Go as far as you can as then slowly return to basic position