Smoking may affect a person's ability to conceive, adding another concern for people planning to start a family.
The World Health Organization (WHO) examined evidence on tobacco use and reproductive health.
The findings highlight why avoiding tobacco is an important consideration for people thinking about having children.
For people hoping to have a baby, fertility can be affected by a number of factors, including tobacco use.
A new knowledge summary from the World Health Organization (WHO) highlights evidence linking smoking to fertility problems in both men and women.
The findings are especially relevant given that infertility affects an estimated one in six people of reproductive age worldwide at some point in their lives. WHO defines infertility as being unable to achieve pregnancy after at least 12 months of regular, unprotected sex.
How researchers examined the evidence
Rather than conducting one new experiment, WHO brought together findings from existing research examining tobacco use and reproductive health.
One systematic review covered studies published between 2000 and 2026, looking at the relationship between smoking and infertility in women. The summary also drew on a review of 44 studies involving more than 60,000 men to examine how smoking may affect male reproductive health.
Researchers also considered evidence from 21 studies exploring smoking and the outcomes of fertility treatments, including in vitro fertilization (IVF). The summary included research on secondhand smoke exposure and discussed what is currently known about newer products, such as e-cigarettes and waterpipes.
What the findings mean for consumers
The evidence suggests smoking may make it harder for some people to conceive. Women who currently smoke had a 40% higher risk of infertility than women who do not smoke, according to the systematic review. Women who had smoked in the past but no longer smoked had a 25% lower risk than those who continued smoking.
For men, smoking was associated with problems involving sperm quality and sexual function, including erectile and ejaculation difficulties. Researchers also identified issues with sperm movement and shape.
Smoking may also affect the success of fertility treatments. Research cited by WHO linked cigarette smoking to fewer pregnancies and live births following assisted reproduction, with some findings suggesting success rates could be roughly halved.
And the potential risks aren't limited to people who smoke. Exposure to secondhand smoke may increase infertility risk and reduce the chance of conceiving each month.
WHO recommends that healthcare providers discuss tobacco-related fertility risks with people planning a pregnancy and offer proven support to help them quit. Evidence on newer nicotine and tobacco products is still developing, but WHO says they may also pose risks.
The takeaway: avoiding tobacco may be one way people can help protect their reproductive health, although fertility is complex and smoking is only one factor that can affect the ability to conceive.