Nearly two-thirds of women of reproductive age in China are exposed to second-hand tobacco smoke at home and over half are exposed in the workplace, which raises the risk of complications in pregnancy, including stillbirths and infant death.
The findings, released by the World Health Organisation on Tuesday, are from a tobacco survey conducted in China in 2010 by the centers for disease control and prevention in China, the United States and the WHO.
Around 100,000 people die from exposure to second-hand smoke in China each year, in addition to an estimated 1 million people who die from direct tobacco consumption.
Women in rural areas of China were more affected, with almost 3 in every 4 exposed to second-hand smoke at home, compared to just over half in urban areas.
"There is no safe level of exposure to tobacco smoke. Creating 100 per cent smoke-free environments is the only way to protect people from the harmful effects of second-hand tobacco smoke," said Michael O'Leary, WHO representative in China.
"Tobacco use and second-hand smoke exposure in reproductive-aged women can cause adverse reproductive health outcomes, such as pregnancy complications, fetal growth restriction, preterm delivery, stillbirths, and infant death."
About a quarter of China's 1.3 billion people are smokers, or about as many people as there are in the United States. But the country is gradually becoming more aware of this public health problem.
The Ministry of Health warned in May that more than 3 million Chinese would die of smoking-related illnesses annually by 2050 if nothing is done to curb this habit.