Just keep in mind if you do it that way than pregnancy comes out to be 10 months instead of 9. This is the chart I use to help keep it all straight!! Lol
Just for kicks, here's a 40-week comparison:
9 month pregnancy photos - renee herlocker images
33 weeks and 9 months side
I use this!
36 Weeks Fetus
36 Weeks Pregnant ~ 9 Months!
9 months weeks