Nearly half the women who have abortions do not use any form of birth control, the China Daily said, citing Wu Shangchun, a division director at the National Population and Family Planning Commission.
"The challenge of reducing (the number) of women seeking abortions in China is tough," Wu said.
Education on birth control is mainly targeted at young married couples, the report said, while parents remain reluctant to teach their children about sex.
"Sex education needs to be strengthened, with universities and our society giving more guidance," the paper quoted Li Ying, an expert on the subject at Peking University, as saying.
A recent survey at a Shanghai hospital found that less than 30 percent of callers to a health hotline knew how to avoid pregnancy, while only 17 percent were aware of venereal disease, the report said.
The low awareness coincides with a sexual revolution spreading throughout China's once ultra-conservative society on the back of economic reform and greater personal freedom.
According to the China Daily, the real number of abortions is likely higher than 13 million, a figure that has already been extensively reported in state media.
The figure is based on data collected from registered abortion clinics, while many terminations take place at unregistered clinics, it said.
Furthermore Chinese doctors annually prescribe up to 10 million abortion-inducing pills that are used in the early stage of pregnancy, it added.
Abortions in China cost about 600 yuan (88 dollars), the report said, with doctors not required to ask the marital status of women patients.
China, which has about 20 million births a year, makes abortion readily available as the government is intensely worried that the population may grow too fast.
At 1.3 billion, China's population is the world's largest, but it has been kept in check by a policy forcing most urban couples to have only one child.