For couples hoping to conceive, tobacco may be an overlooked barrier. Experts now warn that smoking can harm fertility in both women and men by up to 40 per cent, while quitting and avoiding second-hand smoke may improve their chances of having a baby.
For couples struggling to conceive, the cause may lie not only in a medical condition but also in a habit that has long been associated with cancer and lung disease. Tobacco smoking, exposure to second-hand smoke and the use of other tobacco and nicotine products may be reducing their chances of having a baby.
A new World Health Organization (WHO) knowledge summary released on September 8, 2026, brings together decades of evidence linking smoking to infertility in women and reproductive dysfunction in men. It also offers an important message for people planning a pregnancy: that quitting may improve their chances of conceiving.
Women who currently smoke have a 40 per cent higher risk of infertility than non-smokers, according to a systematic review of studies conducted between 2000 and 2026. WHO illustrates the difference by showing that, where the risk among non-smokers is 15 per cent, it rises to 21 per cent among smokers.
The findings do not mean every smoker will experience infertility, or that tobacco is responsible for every couple’s difficulty conceiving. They do, however, identify a preventable risk that deserves attention before and during fertility treatment.
Globally, approximately one in six people of reproductive age experience infertility at some point in their lives. WHO defines infertility as the failure to achieve pregnancy after 12 months or more of regular, unprotected sexual intercourse.
Kenya-specific research provides a clearer picture of the burden. A 2024 study published in Human Reproduction, using nationally representative survey data from four sub-Saharan African countries, estimated 12-month infertility prevalence at 24.5 per cent among Kenyan women actively trying to conceive.
These findings challenge the tendency to treat infertility primarily as a woman’s problem
Infertility can arise from female, male, or combined factors, while some cases remain unexplained. A WHO multi-country study involving 8,500 couples in 25 countries attributed 30.6 per cent of cases to female factors alone, 18.7 per cent to male factors alone, 26.3 per cent to both, and 10.8 per cent to unexplained causes. Male factors contributed wholly or partly to 45.1 per cent of cases.
These findings challenge the tendency to treat infertility primarily as a woman’s problem. They also reinforce the need to assess both partners rather than assume that one person is responsible.
The evidence linking cigarette smoking to female infertility stretches back decades. A 1979 United States Surgeon General’s report identified an association with infertility and abnormal menstruation, while a 1998 review of 12 studies found that female smokers faced an average infertility risk 1.5 times that of non-smokers.
Subsequent research has linked smoking to delayed conception, whether a woman is trying for her first child or another pregnancy. The latest WHO review also found that women exposed to second-hand smoke, despite not smoking themselves, had a 20 per cent higher risk of infertility. Such exposure may also reduce the chance of conceiving in any given month.
For women who smoke, cessation offers a possible way to reduce that risk. Former smokers may have a 25 per cent lower risk of infertility than women who continue smoking, according to the review. The finding suggests that quitting can improve the prospects of pregnancy, although it does not guarantee conception or reverse every cause of infertility.
WHO also identifies substantial evidence linking cigarette smoking to impaired male reproductive health. A review of 44 studies involving more than 60,000 men found associations between smoking and reproductive dysfunction, including semen abnormalities and sexual dysfunction.
Tobacco exposure can also damage sperm quality, affecting sperm numbers, shape and movement towards an egg
Smokers were more likely to experience erectile dysfunction and ejaculation problems. Smoking may also increase the risk of having no sperm in the ejaculate, poor sperm movement, or abnormally shaped sperm, problems that can interfere with the ability to achieve pregnancy.
Dr Charles Muteshi, a gynaecologist and fertility specialist at Aga Khan University Hospital, explains that reproductive cells are particularly vulnerable to toxic exposure.
“Tobacco contains substances toxic to human tissue,” he said. “Cells responsible for fertility are extremely sensitive because they are highly specialised cells. Subjecting them to tobacco products results in change in their functioning in terms of numbers, their shape and even motility.”
Nicotine can constrict blood vessels, reducing blood flow and oxygen delivery to the testes. Tobacco exposure can also damage sperm quality, affecting sperm numbers, shape and movement towards an egg.
Muteshi cautioned against attributing every case of male infertility to smoking.
“There is no study that can say infertility in men is entirely related to tobacco,” he said. “However, we see a high number of men having fertility-related problems linked to reduced sperm numbers, sperm quality, how they appear and movement.”
Weight, alcohol and substance use may also contribute to fertility problems. Other causes include hormonal imbalances, anatomical abnormalities, genetic factors and conditions affecting the reproductive organs.
The effects may extend to couples undergoing fertility treatment. A review of 21 studies linked cigarette smoking to fewer pregnancies and live births following assisted reproduction, with the odds of successful outcomes approximately halved. WHO notes, however, that findings are not entirely consistent. A smaller study involving about 300 women found no difference in fertilisation or pregnancy rates between smokers and non-smokers, including users of e-cigarettes or waterpipes.
Muteshi said tobacco use is no longer confined to the older male smokers who traditionally dominated the habit. He is increasingly concerned about younger adults using newer products.
“Younger people mid-20s to early 30s are using shisha, which is highly concentrated tobacco. They are also using e-cigarettes.”
Second-hand smoke is particularly relevant to couples where only one partner uses tobacco
Traditional forms such as chewing tobacco and local pipes now coexist with cigarettes, shisha and vapes, exposing users to different combinations of nicotine and other harmful substances.
“If you expose yourself to tobacco at a younger age and for a longer period of time,” Muteshi warned, “there is a high possibility that your fertility will be affected.”
WHO says the strongest fertility evidence concerns conventional cigarettes, while research on waterpipes, smokeless tobacco and nicotine products remains limited. That uncertainty should not be mistaken for proof of safety.
A United States study involving more than 4,500 women associated ever using e-cigarettes with a 20 per cent reduction in the probability of conceiving. Two studies involving women who smoked cigarettes or waterpipes found similar increased infertility risks, but WHO found no studies directly and specifically assessing waterpipe use and female infertility.
For men, studies suggest waterpipe smoking may reduce semen volume, sperm movement and the proportion of normally shaped sperm. A more recent study found reduced semen volume but no effect on motility, underscoring the need for further research.
Smokeless tobacco includes products such as snuff and chewing tobacco, while e-cigarettes heat liquid to produce an inhaled aerosol that may contain nicotine and other harmful substances. Exposure can occur directly or through second-hand smoke or aerosol.
Second-hand smoke is particularly relevant to couples where only one partner uses tobacco. Muteshi warned that people may underestimate the danger because they are not smoking themselves.
“People may think they are not inhaling, hence protected from the effects. But by virtue of the fact that the smoker is releasing toxic substances in your presence which you are inhaling, it will affect you just the same way as it is affecting the primary smoker.”
His warning reflects the importance of protecting non-smokers, although the WHO evidence does not establish that active and passive smoking carry identical reproductive risks. The review specifically found a 20 per cent higher infertility risk among women exposed to second-hand smoke.
“When a wife tells the husband to stop (smoking) and he continues, it should be declared as gender-based violence”
The findings arrive as Kenya debates tighter tobacco regulation. The Tobacco Control (Amendment) Bill, 2024, sponsored by Senator Catherine Mumma, seeks to strengthen regulation of emerging products, including vapes and nicotine pouches.
The Bill was passed by the Senate in March 2026 and had its First Reading in the National Assembly in April, after which it was referred to the Departmental Committee on Health for consideration. It, however, faces fierce resistance, with industry players warning that enactment of the bill could lead to massive business losses, including an estimated Ksh12 billion drop in annual government revenue.
However, Joel Gitali, Chairman of the Tobacco Control and Health Promotion Alliance, says fertility should become a more prominent part of tobacco-control messaging.
“People only know tobacco and alcohol cause cancer and cardiovascular diseases and halt it there. What they do not know is that tobacco and nicotine go deeper into causing infertility,” he said.
He wants stronger policy advocacy, public awareness and enforcement, including fertility education in school biology curricula and advice from clergy to couples preparing for marriage.
“Policies must be looked into for gaps, and tobacco control intensified in the country. This will reduce infertility rates if proper policy development and implementation is done.”
Gitali also raised concerns about weak enforcement of restrictions on tobacco displays and sales to people under 18, the ease of purchasing products online and inadequate designated smoking zones. He also expressed concern that some tobacco-control proposals developed jointly by health authorities and advocates have yet to be implemented.
“WHO, the Ministry of Health and the Tobacco Control and Health Promotion Alliance worked on a proposal, but it has not seen the light of day in terms of implementation,” he said.
The scale of tobacco use adds urgency. WHO estimates that approximately 1.2 billion people use tobacco globally, with around 80 per cent living in low- and middle-income countries. A WHO-based estimate for 2022 placed Kenya seventh in Africa by number of tobacco users, with 3.1 million people aged 15 and above using tobacco.
Gitali argues that protecting families from second-hand smoke should be a priority. He says women and children bear a particularly heavy burden and calls for stronger legal consequences when smokers expose family members against their wishes.
“When a wife tells the husband to stop, and he continues, it should be declared as gender-based violence.”
He also described persistent exposure as “like attempting murder” and argues that family homes should fall within public-smoking restrictions. These are his advocacy positions, not established interpretations of Kenyan law.
Support options include telephone quit lines, mobile messaging, digital tools and approved medicines
The Tobacco Control Act, 2007, protects people from second-hand smoke and places responsibility on heads of families to safeguard children. It prohibits smoking in specified public places and residential premises where children are cared for, as well as smoking in private vehicles carrying children.
The Harm Reduction Bill, 2025, sponsored by Nairobi Woman Representative Esther Passaris, offers another potential avenue for supporting people with substance-use disorders by seeking to establish a legal framework for rehabilitation and harm-reduction services in public health facilities.
WHO recommends that healthcare providers routinely offer every tobacco user brief quitting advice lasting between 30 seconds and three minutes. It also encourages fertility information for people of reproductive age and low-cost lifestyle advice before and during infertility treatment.
Muteshi said doctors already ask about smoking and alcohol during routine medical histories, allowing them to identify risks and offer preventive advice. Some facilities also provide addiction services, although he acknowledges that cessation support is not necessarily delivered through a large-scale programme.
Kenya has recently taken a step towards strengthening that response. In June 2026, the Ministry of Health, with WHO support, revised the National Tobacco Cessation Guidelines to align them with evidence-based treatment recommendations and provide a pathway for expanding cessation services.
WHO recommends combining brief advice with behavioural and pharmacological support where appropriate. Options include telephone quit lines, mobile messaging, digital tools and approved medicines. At population level, it supports tobacco taxes, advertising restrictions, standardised packaging and protection from second-hand smoke under the WHO Framework Convention on Tobacco Control.
For men concerned about fertility, Muteshi said quitting may allow sperm quality to improve over time, and “After about three to six months we may see an improvement.”
He noted that the practical response is not simply to warn couples about tobacco, but to help them stop using it, protect non-smokers, assess both partners when pregnancy is delayed, and ensure that fertility services include cessation support.
