I prefer the #1 image as it looks more "natural." The light and the background color make this. The skin tone looks better too. A beautiful woman in a very nice maternity image.
I like first better as well.
I especially like the top she is wearing. Too many Maternity shots use what I can breast straps or other "unnatural" coverups for the breasts.
This on the otherhand is real clothing that permits emphasising the tummy.
The dark background of the first image makes me favour it over the second. In #1 the brightest part of the picture is the face and the belly - just as it should be. Nice work. I look forward to more, and baby pics later.