Fertility at Risk: Smoking Can Reduce the Chances of Conceiving, WHO Warns

Infertility affects around one in six people of reproductive age during their lifetime and is defined as the failure to achieve pregnancy after 12 months or more of regular unprotected sex.

Smoking may affect a person's chances of conceiving, according to a new World Health Organization knowledge summary that brings together decades of research on tobacco use and reproductive health. The findings connect smoking with a greater risk of infertility in women, changes in sperm quality and sexual function in men, and reduced success rates for some fertility treatments. Exposure to second-hand smoke may also create reproductive risks, showing that the concern extends beyond people who actively use tobacco.

Infertility affects around one in six people of reproductive age during their lifetime and is defined as the failure to achieve pregnancy after 12 months or more of regular unprotected sex. Many biological, medical, environmental and lifestyle factors can contribute to it, and the WHO publication places tobacco use among the preventable risks that deserve greater attention during pregnancy planning and fertility care.

Women Who Smoke Face a Higher Infertility Risk

A systematic review covering studies published between 2000 and 2026 found that women who currently smoke tobacco had a 40% higher risk of infertility than women who did not smoke. Tobacco smoke contains chemicals that may affect hormone activity, ovarian function, egg quality and other reproductive processes involved in conception, although individual risk can vary according to smoking history, health and exposure levels.

Women who had smoked previously but no longer used tobacco showed a 25% lower infertility risk than women who continued smoking. This association suggests that stopping tobacco use may improve reproductive prospects, while also protecting future pregnancies and supporting wider improvements in cardiovascular and respiratory health.

Male Fertility and Sexual Health Can Also Be Affected

Infertility is often treated as a women's health issue, yet male reproductive health contributes to many difficulties experienced by couples trying to conceive. A review of 44 studies involving more than 60,000 men linked smoking with semen abnormalities and sexual dysfunction, including erectile dysfunction, ejaculation problems, absence of sperm in semen, reduced sperm movement and abnormal sperm shape.

Healthy sperm need sufficient numbers, normal structure and strong movement to reach and fertilize an egg. Smoking-related damage in any of these areas may reduce the likelihood of natural conception, while sexual difficulties can make pregnancy harder to achieve. These findings support a shared approach to fertility care in which both partners receive clear information, appropriate testing and practical help with quitting tobacco.

Smoking May Reduce the Success of Fertility Treatment

Tobacco use may also affect people receiving assisted reproductive treatment. Research drawn from 21 studies associated cigarette smoking with fewer pregnancies and live births following procedures such as in vitro fertilization, with some findings suggesting that successful outcomes could be roughly halved among people who smoke.

The risks may reach people who have never smoked themselves. Women exposed to second-hand tobacco smoke may face a higher risk of infertility and a lower chance of conceiving during each month they try. Creating smoke-free homes, workplaces and public spaces can therefore protect reproductive health as well as reduce the better-known dangers of tobacco exposure.

Evidence concerning e-cigarettes, waterpipes and smokeless tobacco remains limited and continues to develop. Cigarette smoking currently has the strongest research base, yet the WHO cautions that other tobacco and nicotine products may also threaten fertility and should not be viewed as harmless alternatives.

The WHO recommends that health-care professionals speak with individuals and couples planning a pregnancy about the possible reproductive effects of tobacco use. Every tobacco user should receive brief quitting advice during health-care visits, along with access to evidence-based support that can make stopping more achievable. Quitting may not resolve every cause of infertility, but it removes a preventable risk and gives people a healthier foundation for conception, pregnancy and family life.