Andrea Leadsom says she has apologised to her Tory leadership rival, Theresa May, over comments made to a Times journalist, in which she suggested that being a mother gave her more of a stake in the future than May, who does not have children.

Leadsom, who told the Telegraph she was pressed into making the comparison, said after the story was made public she had felt “under attack, under enormous pressure … It has been shattering.”

When asked if she had apologised to the home secretary for the comments, Leadsom said she had, but declined to say if it was in person. “I’ve already said to Theresa how very sorry I am for any hurt I have caused and how that article said completely the opposite of what I said and believe,” she said.

“I was pressed to say how my children had formed my views. I didn’t want it to be used as an issue. Having children has no bearing on the ability to be PM. I deeply regret that anyone has got the impression that I think otherwise.”

Leadsom will compete with May to win the support of Conservative members who will decide the next prime minister. May is due to formally launch her leadership campaign on Monday. Leadsom provoked a furious reaction on Saturday after she told the Times: “I feel that being a mum means you have a real stake in the future of our country, a tangible stake.”

She later tweeted the journalist Rachel Sylvester, calling the piece “gutter journalism” and the paper released the audio and transcripts of the interview.

In the wake of her Times interview, business minister Anna Soubry said Leadsom’s comments meant she was “not PM material” while Scottish Tory leader Ruth Davidson said there was a “gulf in class” between the two candidates and senior MP Sir Alan Duncan said the energy minister’s remarks were “vile”.

Tim Loughton, Leadsom’s campaign manager, called the criticism “the establishment trying to get Andrea” and that she should not be deterred from making her family part of her appeal as a candidate.

“What she is saying she is passionate about her kids. Since when has it been a crime to be proud about your children?” he said.

Iain Duncan Smith, the former work and pensions secretary who is one of Leadsom’s most high-profile supporters, said she was “genuinely mortified” but added he believed “we’ve had a real black operation to denigrate her”.

Eric Pickles, the former cabinet minister who is supporting May’s bid, said he did not believe Leadsom’s campaign was irrevocably damaged, though he said she had had what could “charitably be described as a disastrous start to her campaign” with her motherhood comments and questions being raised over her City career.

“She gave a bad interview, her first major interview with a very serious journalist and she fluffed it, she messed it up and to make it worse, she then accused that very senior journalist of engaging in gutter politics,” he told Sky News.

“I don’t like to see those kind of reactions in a potential prime minister because she is going to have to deal with a lot more [and] tougher people than that particular journalist, Rachel Sylvester. I think Mr Putin might be just a little bit more difficult.”