JOIN USThe report also found that the number of pregnant women dying has decreased by 34% from an estimated 546 000 in 1990 to 358 000 in 2008.
The resulting 2.3 per cent annual rate of decline, however, is less than half of what is needed to achieve the MDG of reducing the maternal mortality ratio by 75 per cent between 1990 and 2015.
"To achieve our global goal of improving maternal health and to save women's lives we need to do more to reach those who are most at risk," said Anthony Lake, head of UNICEF.
"That means reaching women in rural areas and poorer households, women from ethnic minorities and indigenous groups, and women living with HIV and in conflict zones."
The four main causes of pregnancy related deaths have been identified as severe bleeding after childbirth, infections, hypertensive disorders, and unsafe abortion.
Out of the 1000 pregnant women who died in 2008, 570 lived in sub-Saharan Africa, 300 in South Asia and five in high-income countries, the UN said.
The risk of a woman in a developing country dying from a pregnancy-related cause during her lifetime is about 36 times higher compared to a woman living in a developed country, according to the report.
"Maternal deaths are both caused by poverty and are a cause of it. The costs of childbirth can quickly exhaust a family's income, bringing with it even more financial hardship," said Tamar Manuelyan Atinc, Vice President for Human Development at the World Bank.
Earlier this week, Secretary-General Ban Ki-moon announced that he will launch a 'Global Strategy for Women's and Children's Health' during the summit next week expected to attended by more than a hundred world leaders including US President Barack Obama.
"We cannot accept this intolerable situation where many millions of women die needlessly in the course of their child birth or pregnancy… which can be easily be prevented," Ban told journalists.
"No area has more potential to set off a ripple effect -- a virtuous cycle -- across the Goals than women’s health and empowerment," he added.
To achieve the health MDGs, Ban noted that the international community had to invest an additional 26 billion dollars by 2011 in 49 lowest income countries, and 42 billion by 2015.