And to me, it tells us that what matters the most, what looms the largest, in this couple's life is the birth of a child, soon to be a real presence (using imagination reading the pix here, who knows, they could break up tomorrow...) in their entire life. The poster does not seem so big anymore, then...
How wonderful, we do not see them, but their gaze is unmistakable, the man himself seems to reach closer to her with his arm. Even if their thoughts were to be more prosaic, their body language tells us much.
****What I like about this image is the incongruity of the giant child overwhelming the two thoughtful "parents" to be. You get the sense that they stand in awe of the responsibility of having and raising a child.