The mother was aware another Queenstown teenager was applying for both schools and in an effort to have her daughter accepted ahead of the other pupil, she made the fictitious calls.
In October, the woman admitted using a telecommunication device to knowingly give a fictitious message - namely that she was a sexual health worker and the other girl had a sexually transmitted disease, was in a lesbian relationship and wanted her to make an appointment with the clinic; and in a separate charge, that the child needed support with treatment.
In the first call, to St Hilda's about a boarder needing support with treatment, the woman then said she'd made a mistake and was calling in relation to a prospective pupil, before naming the girl.
In a second call, to Columba, she said the prospective pupil had a sexually transmitted disease and that she was in a lesbian relationship with another girl.
Defence counsel Phena Byrne read an apology the defendant had sent to the schools and the complainant.
The victim attended yesterday's sentencing and was visibly upset throughout, at times sobbing.
Judge Neave said the defendant's behaviour was scandalous.
"It was a deliberate attempt to [get your daughter preferential entry].
"The effects ... have been utterly devastating for the complainant. The effects on her will be long-lasting. I can only pray they won't be permanent."
He said the woman suffered from "very serious mental health issues".
The judge gave the woman credit for her guilty plea and for doing "what little you can" to acknowledge the wrongdoing and apologise.