This is just getting more and more into the realms of the unrealistic; I mean, yes, she probably could be but if that was a reasonable likelihood then surely the defence would have investigated that possibility?
Also, what diseases are out there which can be carried asymptomatically which, coincidentally (conveniently) only manifest in pre-term babies, only whilst the carrier is the only other human nearby and which often disappear leaving no trace when resus is performed?
With the greatest of respect, what you appear to be doing here is simply looking for random answers which might make her innocent rather than actually looking at the evidence we currently have and weighing that against guilt or innocence. Conformation bias, essentially.That is not the way that murder investigations are carried out.