Today Gordon and I are in Hokkaido in northern Japan for the G8 summit, where he and other world leaders will together address some of the most important issues facing the world.

With oil prices, food prices and the economic downturn affecting people in all the richest nations, their leaders could be forgiven for concentrating on those issues to the exclusion of all others.

But in Tokyo yesterday I joined the Japanese Prime Minister's wife, Mrs Fukuda, to raise awareness of an issue that we argued the G8 leaders must find time to discuss.

Across the world this year, more than half a million mothers will lose their lives in pregnancy or childbirth - almost all in poorer countries. One death every minute.

For every mother that dies, 30 other women are left suffering from injuries and disabilities as a result of complications in childbirth.

The scale of this tragedy becomes even more horrific when we consider two facts.

First, that for all the progress the world has made over the past 20 years, the number of mothers dying in childbirth remains exactly the same as in the mid-1980s.

Second, that almost every one of these deaths is totally preventable. Because these are not deaths caused by killer diseases. They are caused because there are no clamps to stop a mother's bleeding or no health worker to hold them. They are caused because there is no one to dispense the 2 pence worth of magnesium sulphate required to stop a mother dying from the high blood pressure associated with pre-eclempsia. They are caused because mothers giving birth on the floor or using dirty equipment are vulnerable to infections, and lack the medicine to treat them.

The world currently has a global shortage of four million skilled birth attendants, which is why half of the women in the world still give birth alone, or at home with only a neighbour to help.

In 2000 the United Nations established maternal mortality as one of its eight millennium development goals, and set a target that should have been one of the more easily achievable: to reduce the numbers of mothers dying in childbirth by three quarters by 2015. But eight years on, more than halfway to the target date, little progress has been made.

Yet saving the lives of mothers is one of the most crucial steps towards achieving some of the other vital millennium development goals, including cutting infant mortality, and educating and vaccinating all children. It is the mothers that survive who feed their children, get them into a school and take them for their vaccinations. By contrast, children who have lost their mothers are almost five times more likely to die in infancy.

We need to make 2008 the turning point in the battle against maternal deaths. Momentum is building. Never before has this issue had so much visibility and support.

A new coalition of governments, charities and private sector backers has come together under the banner: Promise to Mothers.

Save the Children, Oxfam and Comic Relief are making the issue a priority this year, joining grass-root movements such as the White Ribbon Alliance, which has been campaigning for progress. And the world's midwives, obstetricians and gynaecologists are working together to support developing countries in training their birth attendants.

The G8 leaders in Hokkaido have their chance this week to contribute to this gathering global effort. Most importantly, they can address the shortage of skilled birth attendants and health workers, with a package of aid for their recruitment and training, and funds so they can be deployed in every community that needs them.

What should drive them to that agreement is not just the scandal that so little progress has been made for the past 20 years, but the clear evidence that, where there is proper investment, the results can be dramatic.

Through my work as Patron of the White Ribbon Alliance, I have visited countries where remarkable change is taking place. In Babati, Tanzania, hard-pressed, over-stretched midwives took cameras in to their communities to record the realities of maternal health care. They captured images of hundreds of women walking across the bush and lining up all day to see one nurse or midwife. They filmed babies born on the road; maternity wards with three women to a bed and three on the floor in between. The footage was shown on television in Tanzania, and it encouraged President Kikwete to make maternal and infant health a priority and double the number of midwives.

In India, the White Ribbon Alliance successfully advocated policy changes to enable auxiliary nurse-midwives to perform life-saving procedures and provide essential drugs.

It is decisions like these, backed with real aid getting to the people who need it, that can put an end to the daily toll of maternal deaths, and to the hundreds of babies every day orphaned at birth.

This is a global tragedy that must be brought to an end, but it is a problem that we know how to solve.

From individuals raising awareness, to communities coming together and the charities working on the ground, right up to the actions of world leaders this week in Hokkaido, we can all make a contribution. We have a unique opportunity to make the breakthrough, and we know we cannot wait another year, let alone another twenty years.

In my discussions with Mrs Fukuda, Mrs Sarkozy and Mrs Bush, I know they all understand the urgency of this issue. Now it is over to our husbands, and to the other world leaders.

The time for action is now. We owe it to the millions of mothers who have lost their lives unnecessarily over the past 20 years. We owe it to the thousands of pregnant women around the world giving birth every day in fear of their lives. We owe it to the next generation of babies born in the poorest countries of the world. Babies who need their mothers.

Sarah Brown is Patron of the White Ribbon Alliance

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