[Photo by Gong Bo/For China Daily]

The WHO defines maternal mortality as "the death of a woman while pregnant or within 42 days of termination of pregnancy".

At the end of last year, China's top leadership approved a change in national policy to allow all couples to have a maximum of two children.

Of the 90 million women who became eligible to have a second baby, 60 percent are more than 35 years old, a group considered to be subject to greater risk, according to the commission.

The increase in the number of pregnant women, particularly of those at higher risk, such as older women, has resulted in an increase in maternal deaths in the first half of the year, the commission said.

In addition, the sudden rise in pregnancy also put new strains on maternal health services, and both facilities and hospital staff are underequipped, the commission said.

Gu Hong, a pediatrician at Beijing's Anzhen Hospital, said the number of pregnant women with cardiovascular complications received by the hospital has been increasing in the past few years, and seven pregnant women died from complications in the hospital in the past five years.

"The situation is serious," she said. "Now more women are trying their best to have a second child, including some who face life-threatening risks, such as those with serious cardiovascular disease."