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A Clustered Randomized Controlled Trial to Reduce Secondhand Smoke Exposure among Non-smoking Pregnant Women in Sichuan Province, China

2015 | Nicotine and Tobacco Research

A health education intervention for non-smoking pregnant women in China’s Sichuan province, conducted by researchers from PHI's Center for International Tobacco Control, has demonstrated a significant reduction in secondhand smoke exposure, according to a new study published in the journal Nicotine and Tobacco Research

China has the world's largest number of smokers, and the vast majority of them are men. Despite only 2.4 percent of women in China being smokers, the majority of women in the country report secondhand smoke exposure. The researchers indicate that exposure is greater for women who are rural, have a husband with greater cigarette consumption, have less knowledge about secondhand smoke, have less negative attitudes about it, and have no smoke-free home rules. According to the Global Adult Tobacco Survey, 65 percent of women of reproductive age (15-49 years old) in China reported high secondhand smoke exposure at home, yet few interventions have focused on pregnant women reducing their secondhand smoke exposure. 

Secondhand smoke exposure causes cancer, cardiovascular disease and chronic respiratory illness for the person directly exposed, and can cause harmful effects to the fetus in non-smoking pregnant women, including low birthweight, fetal death, preterm delivery spontaneous abortion, and congenital malformation.

This clustered randomized controlled trial, conducted at eight hospitals in Sichuan, China, compared a prenatal health education intervention with usual clinical care as a control. The primary outcome was self-reported “no secondhand smoke exposure” before and three months after birth. The intervention consisted of three large group educational sessions, standardized clinician advice, brief monthly follow-up calls, and educational materials and resources. A random sample of participants was biochemically validated before birth with hair nicotine, a long-term biomarker of smoke exposure.

The intervention group was less likely to report secondhand smoke exposure than the control group, and this effect was sustained three months after birth. The intervention group also had greater changes in secondhand smoke knowledge and attitudes, and it had more smoke-free home rules and significant decreases in the husband’s daily cigarette consumption. Since most women in China report the home as a secondhand smoke exposure source, this study underscores that establishing and enforcing smoke-free policies at home can significantly reduce secondhand smoke exposure.

The researchers conclude that including this type of education intervention in medical care opportunities with pregnant women seeking prenatal care might protect millions of pregnant women from exposure to secondhand smoke and their children.

Read the full study.


Anita Lee, Zhengzhong Mao, Elisa K. Tong, Lian Yang, Teh-wei Hu

Produced through PHI's:

Center for International Tobacco Control