Hmm sending wife to Vegas
First consult with a Doctor, if wife can fly. I know when I was 6 month preg I was not able to fly.
If she is not able to Fly send her to a local resort Hotel and let her have a fun time
If she is able to fly, Vegas is alwasy good . You can fly great discounts and the Hotels there
Or be romantic Her her just have a time at home hire and Maid for a week let her have the time off. Pamper her