GENEVA (Reuters) - There is no excuse for the fact that pregnancy and childbirth continue to kill 529,000 women and leave 1 million children motherless worldwide every year, the wife of British Prime Minister Gordon Brown said on Tuesday.

"Every health minister should be thinking about this and knowing what their plan is," Sarah Brown told the World Health Organisation's 193 member states at their annual congress.

Simple measures before, during, and after delivery could save women's lives and should be instituted as soon as possible, she told the meeting at the United Nations offices in Geneva.

"There is no longer an excuse not to try," Brown said, building upon a forceful speech by U.N. Secretary-General Ban Ki-moon who called it "an outrage" that countries have done so little to improve maternal survival rates.

"Maternal health is a key barometer of a functioning health system," Ban said in his remarks to the World Health Assembly. "In the 21st century, no woman should have to give her life to give life."

Most maternal deaths occur in developing countries, and almost all are due to five causes -- hemorrhage, infection, unsafe abortion, eclampsia, and obstructed labor. The WHO says that surviving children are more likely to die within two years of their mothers' death.

In her remarks, Brown urged officials to "put girls and women at the center of funding for health system strengthening."

"We must find a way to get maternal mortality recognized as a key indicator of a functioning health system," she said. "Let us work together to make sure maternal mortality is a problem of the past and not our children's future."