As Pp have said, there was no mitigating plea that the woman was mentally ill , so I think we can safely assume that her defence team would have thought of that before you.
It may be correct that the woman is just monstrous and cruel and hid her baby with a hare lip as though she were an animal. Or the woman had a primitive belief that the child was cursed. Or, the woman is a child abuser, who picked out this one of her children as a scapegoat to abuse for fun because she enjoys the feeling of power or she has a right to do so because she thinks her daughter is evil and deformed.
Not withstanding that she fed her milk and cereal with a syringe to keep her alive, this could have been the better to prolong the abuse.
But I do not agree that anyone can assume the defence team or the judge would have known that there can in rare circumstances be certain mental effects of giving birth, specifically after denied/concealed pregnancies, that are associated with infanticide (which the woman’s actions in this case possibly echoes in its apparent dissociativeness).
Courts have already shown they do not know anything about this. Infanticide as a discrete charge is somewhat known more widely, but not the links it has to concealed/denied pregnancies. You have to have seen the research to know about it.
As this consideration has apparently not been mentioned it could well be it was not considered.
If this were the by any chance the case, prison per se will do nothing to help, and if this woman were to have another baby when she gets out of prison after the seven years, that baby might be in danger. Alternatively, she could be held and treated in a psychiatric hospital.
Courts do not always have awareness of factors involved in a case. Often for example it is well known they frequently have no idea about what constitutes the behaviours of a rape victim.