There is a scene when Anna is exiting the metro where she begins to thrash around that ends in an upsetting scene where she seems to have a sort of seizure and excretes a foamy liquid from her body.
Not really, but there can be an interpretation. SPOILER: Towards the very end, Anna shoots herself through the lower back as she was dying. I saw this as implication that she tried to make sure an unborn (demon) child did not survive her death, as she was shown having (presumably unprotected) sex with the demonic entity many times before throughout the film.