Minogue filed a complaint with the press watchdog following publication on 9 January of an article headlined "Look who's Xpecting!" in the Mirror and a second the same day in sister paper, the Record, headed: "X Factor Dannii is pregnant".
The papers, which are owned by Trinity Mirror, both reported that Minogue was expecting a baby with her boyfriend, Kris Smith.
Through her representative Minogue complained to the PCC that the papers published their stories knowing she had yet to take her twelve-week scan.
The PCC has previously upheld complaints from Charlotte Church and the actress Joanna Riding about articles which also referred to the early stages of pregnancy.
The newspapers told the PCC they were aware of the general "first scan rule" in regard to pregnancy. However, they claimed news of the pregnancy had been in the public domain before publication, appearing on the Faded Youth blog and on the Sydney Morning Herald website the previous day.
Publishing its adjudication today, the PCC said both the Record and the Mirror claimed that in those circumstances, the news had ceased to be private.
Despite this claim, the PCC ruled that the articles constituted a "regrettable lapse in editorial judgement at the newspaper[s]", adding that it had "no hesitation in upholding the complaint".
The commission's adjudication stated: "For the newspaper to justify publication on this occasion, it would have to argue that the references in the Sydney Morning Herald and online -- which were, in any event, speculative -- made it 'perverse' for it not to have referred to the pregnancy.
"This was manifestly an untenable argument and was rejected by the commission."
The PCC said the editor's code -- to which newspapers should adhere -- specifically required publications to consider the "extent" to which information has previously appeared.
It added: "This was no more than common sense: otherwise, any reference online would represent automatic justification for a newspaper to publish otherwise intrusive material."
The PCC said the newspapers were happy to publish an apology as a gesture of goodwill.
The Daily Mirror also published the PCC adjudication in full on page three this morning.
Oliver Luft writes for Press Gazette