Maternal deaths have fallen by 45% worldwide since 1990, statistics of the UN and the World Health Organization (WHO) show.

Over half a million women died during childbirth in 1990, while in 2013 the figure was 289,000.

The report "Global causes of maternal death: a WHO systematic analysis" reveals that over a quarter of maternal deaths are caused by pre-existing medical conditions such as diabetes, HIV, malaria and obesity.

Sub-Saharan Africa remains the most vulnerable region, with a 1 in 40 risk of death during pregnancy. Europe records the smallest risk, at 1 in 3,300. However, in the United States maternal mortality is on the rise. India and Nigeria hold the highest number of deaths during pregnancy, with 50,000 and 40,000 respectively.

Eleven countries have made steady progress in reducing maternal mortality by 75% or more, envisioned in the Millennium Development Goals. These are Bhutan, Cambodia, Laos, Cabo Verde, Equatorial Guinea, Eritrea, Maldives, Romania, Nepal, Rwanda, and Timor-Leste.

"A major challenge in addressing maternal deaths is the lack of accurate data. Although knowledge on the number of women dying and the reasons behind their deaths is improving, much remains unrecorded and unreported. In many low-income countries, maternal deaths go uncounted and frequently the cause of death is unknown or not recorded correctly, particularly when women die at home", WHO adds.