Smoking and exposure to secondhand smoke are tied to increased risk of infertility, miscarriage, low birth weight, preterm delivery and other adverse pregnancy outcomes, according to a recent study by researchers from Tsinghua University.

The study found that tobacco use among couples — with wives aged 20 to 49 and either or both partners having a habit of smoking — may lead to a total of 9.7 million population loss as a result of infertility, miscarriage and stillbirth. The exposure to secondhand smoke has further resulted in 10.85 million unborn babies.

Furthermore, smoking or breathing secondhand smoke exposure has raised the risk of low-weight birth, preterm birth, congenital heart disease and gestational diabetes by around 25 percent to 72 percent.

The study is led by Li Zhihui, an associate professor from Tsinghua University's Vanke School of Public Health. It has analyzed data collected from a global tobacco use survey and a national database on Chinese families.

Data released by the National Health Commission in 2021 shows that about 26.6 percent of people aged 15 and above, or more than 300 million people, smoked in China. One in two males are smokers and 68.1 percent of its total population are exposed to secondhand smoke.

At the same time, the nation is grappling with a low birthrate and dedicating strong efforts to relieving the childcare burden and promoting high-quality demographic development.

The study suggested authorities implement stronger tobacco control measures, including increasing tobacco tax and implementing smoke-free policies.

It is estimated that a 20 percent rise in cigarette prices will reduce the smoking rate among adults by 3.2 percent, thus resulting in 1.3 million more newborns and preventing more than 680,000 cases of adverse pregnancy outcomes.