Madonna has been comparing the "painful" struggle of her adoption plans with the suffering women go through in natural childbirth.

The singer was at the Cannes Film Festival talking about her new documentary I Am Because We Are, which her adopted child David Banda features as his birth mother died from Aids.

The hard-hitting film concerns the effects of Aids in Malawi - where 1 million youngsters have been left orphans because of the disease.

The documentary, which had its premiere at the Tribeca Film Festival in New York, features interviews with Bill Clinton among others and shows a stark picture of desperate poverty and children orphaned by Aids. It also highlights how education can help the situation.

Madonna said: "To say that this film is a labour of love is true, but that's kind of trivial because really what it is, is a journey of a lifetime."

Asked about the controversy over the adoption process and whether it was to do with karma, she replied: "I suppose everything that happens to me is a karmic thing. It was meant to happen. So yes it was painful and a big struggle and I didn't understand it."

She added: "But in the end I rationalised that when a woman has a child and goes through natural childbirth, she suffers an enormous amount.

"So I sort of went through my own kind of birthing pains, dealing with the press on my doorstep, accusing me of kidnapping or whatever you want to call it. But I had to go through some kind of process and in the end it made me stronger so I can't complain."

She was also asked to clarify whether she believed David's natural mother had died from Aids and whether his father had agreed to the adoption.

The singer replied: "Yes his mother did die of Aids and yes, I met his father and he has absolutely agreed to the adoption."

Asked whether the film was an explanation for why she wanted to adopt David, she said: "There is nothing controversial about the adoption. It is just there's a lot of bureaucracy and administration...This adoption essentially was the beginning of the creation of adoption laws in Malawi...

"I am the template or the role model so to speak for future adoptions."

She said she hoped it would make the process easier for other people to adopt children, continuing: "I am happy to be a guinea pig. The film was not made to explain the adoption."

She said that meeting David, initially seen being cared for by a young girl in the film, illustrated how children looked after other children. "It was an important part of the story," she said.

Madonna said: "I went to Malawi in Africa thinking that I was going to save children's lives and make a big difference in their lives and I was going to effect change in their lives and hopefully I have.

"But the surprise to me was how much they changed me and how much evolution and growth occurred inside of me. I realised that if you really want to change the world, you have to change yourself...

"The other thing is how little it takes to bring joy to people's life, how little it takes to change someone's life."

The singer said she was grateful that the film had generated a buzz and homes for the movie were being found all over the world.

She learned "is that people are the same everywhere".

In a reference to her recent hit song, she was asked what she would do if she had four minutes to save the world.

Madonna joked: "I'd go to Malawi with Justin Timberlake," before adding: "I would have to spend it with my children."

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