Women are very beautiful when they are pregnant. There is a window of time in a woman’s pregnancy, around the 8th month when her belly is large, but she is still comfortable to be photographed. This is the time to capture her beauty.
Hands on the belly is a classic and beautiful pose. I also like hands on heart. This both covers the breasts (more modest) and expresses the blessing that is birth. Try different angles and facial expressions when you photograph a pregnant momma. In this image below we also used a reflector.