According to United Nations figures, some 220 million women in the developing world who don't want to get pregnant can't get reliable access to contraception. They forecast a boom in the world population from 160 million by 2050 to a mammoth 400 million.

And today billionaire philanthropist Melinda Gates will announce a multi-million dollar funding pledge to help improve access to birth control for as many who want and need it. According to The Lancet medical journal the money could reduce the incidences of mother's dying during birth by 30% and could also help save 104,000 lives a year endangered by the complications coming from pregnancy and childbirth.

Large scale programmes to tackle malaria, AIDS and tuberculosis across Africa and India have all been funded with around $1.4bn by The Gates Foundation – the charity set up with her husband, the founder of Microsoft empire, Bill Gates. At a summit today Melinda is set to offer more millions.

Melinda Gates said: "We can put a certain amount of money in, but the causes that we have picked around the world are so enormous that they take governments to come in and really fund them at large-scale. What a foundation can do is show some ways, take some of the risk out of the equation, put some of the innovation in, but ultimately it is governments that need to come in and fund them and that is what makes me exited about the London Family Planning Summit is you are going to see government commitments to this as well"

The Gates have been criticised for getting involved in the issue because of the major cultural barriers in some developing countries when it comes to trying to limit the size of a family, but also morally. Many Catholics think there's a fine line between contraception and abortion. And there's plenty of controversy around the fact that money isn't the only barrier to contraception. The aim of today's London Summit on Family Planning is to raise 4 billion US dollars to expand access to contraception for 120 million women in the developing world by 2020.

Written & Presented by Marverine Cole