I must start off by saying that I think that Gary Fry is a very good writer and, as appreciation of any story is subjective, no one can expect to connect with everything every writer writes. This one just was sort of “meh” for me. High points for creepiness and good writing. I thought the changes that were tormenting the main character were quite well done. The points off are contained in the spoilers, however.
It must be said that Fry is treading very familiar ground with a story of this type---pregnant woman feels that something is wrong, even sinister, with her soon to be born child---so comparisons are to be expected. This one to make it stand out required a heavier touch than I am used to from Fry, who is more subtle and traditional (see his wonderful novella “Emergence” or even “Lurker” which is darker but still very traditional) in style. Ira Levin wrote the definitive story of this type a long time ago and as a recent example Tim Curran’s “Sow” (also from Darkfuse) is similar conceptually, but goes for the throat from the outset and leaves you shaking and disturbed.