Quitting Smoking May Matter Earlier in the Journey to Parenthood Than Many Think

Smoking may be undermining fertility long before pregnancy begins. A World Health Organization (WHO) knowledge summary links tobacco use to higher infertility risk in women, poorer sperm quality and sexual function in men, and lower success rates for some fertility treatments.

With infertility affecting around one in six people of reproductive age, the WHO's findings widen the tobacco debate beyond pregnancy itself. They put smoking firmly into the pre-conception conversation, as a potentially preventable risk affecting both partners.

Fertility Risk Begins Before Conception

A systematic review of studies published between 2000 and 2026 found that current smokers had a 40% higher risk of infertility than women who did not smoke, adding weight to concerns about tobacco's effects on reproductive function.

Tobacco smoke contains chemicals that may interfere with hormone activity, ovarian function and egg quality, all of which can influence conception. The findings do not mean smoking alone determines whether someone becomes pregnant, but they strengthen the case for treating tobacco exposure as one factor within a much wider fertility assessment.

The difference between current and former smokers is also notable. Women who had previously smoked but stopped showed a 25% lower infertility risk than women who continued smoking, suggesting that cessation may improve reproductive prospects even before pregnancy occurs. Instead of waiting until a pregnancy is confirmed, reproductive health services may need to address smoking earlier, particularly when individuals or couples begin planning a pregnancy or seeking help for difficulty conceiving.

Male Fertility Makes Tobacco a Shared Reproductive Issue

Infertility is often discussed through the lens of women's health, but the evidence on male reproductive health shows why that framing is incomplete. A review of 44 studies involving more than 60,000 men linked smoking with semen abnormalities as well as sexual dysfunction.

The reported problems included reduced sperm movement, abnormal sperm shape, absence of sperm in semen, erectile dysfunction and ejaculation difficulties. Because conception depends partly on sperm number, structure and movement, changes in any of these areas can reduce the likelihood of fertilization.

The implication is that fertility counselling should not place responsibility primarily on women. Tobacco use is relevant to both partners, and screening, testing and quitting support may be more effective when fertility care treats reproductive health as a shared issue.

This is also important for how risk is communicated. Smoking should not be presented as the explanation for every fertility problem, nor should individuals be blamed for infertility. But where tobacco use is present, it represents one modifiable exposure that can be addressed alongside other medical and reproductive factors.

IVF and Fertility Treatment Raise the Stakes Further

The impact of smoking may become even more consequential when people turn to assisted reproductive treatment. Research across 21 studies associated cigarette smoking with fewer pregnancies and live births following procedures such as in vitro fertilization.

Some findings suggested that successful outcomes could be roughly halved among people who smoke. That does not mean every smoker undergoing fertility treatment will experience the same result, but it raises an important clinical question about whether tobacco cessation should become a more integrated part of fertility-treatment planning.

Assisted reproduction already involves significant medical intervention and emotional investment. If smoking is associated with poorer treatment outcomes, fertility clinics have a strong reason to discuss tobacco use not simply as a general health issue, but as part of the wider reproductive-health picture.

At the same time, caution is essential. The evidence describes associations rather than guaranteed outcomes, and fertility-treatment success depends on many factors, including age, underlying reproductive conditions and overall health. Quitting smoking cannot be presented as a cure for infertility.

Second-Hand Smoke Expands the Problem Beyond Smokers

The reproductive risks do not stop with people who actively use tobacco. Women exposed to second-hand smoke may also face a higher risk of infertility and a lower chance of conceiving during each month they try, widening the issue from individual behaviour to shared environments. This gives smoke-free homes, workplaces and public spaces an additional reproductive-health dimension. For couples trying to conceive, exposure may matter even when neither partner identifies as an active smoker, reinforcing the importance of reducing tobacco smoke in everyday surroundings.

There is still less certainty around e-cigarettes, waterpipes and smokeless tobacco. Cigarette smoking has the strongest evidence base, while research on other tobacco and nicotine products remains limited, making it difficult to draw equally firm conclusions about their effect on fertility.

The WHO recommends that health-care professionals discuss the possible reproductive effects of tobacco with people planning pregnancy and provide users with brief quitting advice and access to evidence-based support.

The significance of that recommendation goes beyond smoking cessation itself. It reflects a broader shift in reproductive health toward acting before pregnancy begins, when preventable risks can still be reduced and when both partners can be brought into the conversation.

Smoking does not explain every case of infertility, and quitting cannot guarantee conception, but the evidence increasingly places tobacco within the fertility equation, making pre-conception care, second-hand smoke protection and shared reproductive counselling more important long before a pregnancy test turns positive.