It's an odd verdict, though. It looks, on the face of it, as though she has been convicted on the strength of having lethal drugs in her house, being devious in her acquisition of them, having medical training and being the parent of a dead baby (ie, the prosecution, jury and the judge took a dislike to her.)
In order to justifiably be found guilty you'd have supposed that the prosecution would need to show how the drugs were administered, not guess. Someone else could have done it, or it could have been accidental. The fact that the tooth fairy's breast milk, conceivably might have poisoned the baby is irrelevant.
I'm not particularly sympathetic towards the mother, but the judgement is ridiculous.