The Daily Mirror publisher said group revenue fell by 16% for the four months to 30 April, or 9% on a like-for-like basis.
One-off costs would include spend on the launch of The New Day newspaper, which closed less than three months later. The cut-price newspaper’s demise was reported exactly a year ago today.
Publishing revenue also fell by 9% on a like-for-like basis, with print declining by 12% and digital growing by 6%.
Print ad revenues fell by 19% and circulation revenues fell by 6%.
This decline is consistent with the 18% fall in print ad revenues Trinity Mirror reported in its 2016 financial results, when it reported a 14% growth in pretax profit.
Despite Trinity Mirror growing its digital audience, with digital display and transaction revenue growing by 19%, digital classified advertising fell by 24%. The company said digital classified ads are predominantly upsold from print.
Simon Fox, chief executive of Trinity Mirror, said: "While the trading environment for print remains challenging we continue to make progress on our strategic objectives of Grow, Build and Protect.
"I am particularly pleased that we continue to see good growth in digital display and transactional revenue and tightly manage costs, which gives confidence in our performance for the year."