Some 13 million abortions are carried out in China each year, in part because there is little education about contraception or disease for the rising numbers of young people who are having sex, state media said on Thursday.
Fewer than one in three callers to a Shanghai hotline knew how to avoid pregnancy, and only one in five were informed about venereal disease, the official China Daily quoted a survey by the city's 411 Army Hospital saying.
"Sex is no longer considered taboo among young people today, and they believe they can learn everything they need from the Internet. But it doesn't mean they have developed a proper understanding or attitude toward it," the paper quoted hospital gynaecologist Yu Dongyan saying.
Until the 1990s, doctors asked for women's marital status at abortion clinics, which were part of the family planning system that limited urban couples to one child.
Now, government data shows that nearly two thirds of women who have abortions are between 20 and 29, and most are single, the paper said.
Birth control information is mainly given to young couples.
Some single women may also be driven to seek abortions because under current laws unmarried mothers cannot get a "hukou" or household registration card for their child.
Without one it is extremely hard for Chinese citizens to get access to education, healthcare and other public services. China also sells about 10 million abortion pills a year, and there are many other abortions performed in unregistered clinics, the paper quoted Wu Shangchun, a division director at the National Population and Family Planning Commission, as saying.
In the United States, by contrast, which has a population less than one-quarter that of China, official figures from the Centre for disease control show there were 820,000 abortions performed in 2005, excluding California, Louisiana and New Hampshire for which no figures were provided.
Sun Xiaohong from the education department of Shanghai's family planning authority said it was difficult to promote sex education in schools because some teachers and parents thought it would encourage teenagers to become sexually active.
Ordinary web users in China will be banned from surfing sex-related medical and research websites from July, amid an Internet crackdown on pornographic online content, that threatens to make information about sexual health even harder to access.