For me, the second image doesn't work. One of the booties is just barely out of frame and, outside the context of the other photos, how would one know it is a maternity photo?
The last image is the best, with nice light and composition.
My Pregnancy Photography Guide:
|Black on White by RaVN11|
|Hummingbird and Bee by dibilio57|
from A Big Year - birds
|xheneta iseni _for DPReview by Mike Slade|
from - My Fair Lady - (Portraits in Full Colours Only + A Border)