Does Smoking Affect Fertility? What Happens to Eggs, Sperm, and Your Chances of Getting Pregnant

Quick answer: Yes, smoking can affect fertility in both women and men, although this does not mean that a person who smokes cannot get pregnant. The effect depends on how much someone smokes, for how long, and on each individual. Some aspects of reproductive health can improve after quitting.

Here we explain what we know about smoking and fertility, vaping, and what can change when you stop.

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How does smoking affect fertility?

Cigarette smoke contains more than 7,000 chemicals. Some pass from the lungs into the bloodstream and can reach the ovaries, the testicles and other organs.

It is not only about nicotine. Smoke also contains carbon monoxide, heavy metals and other substances that increase oxidative stress. In simple terms, this happens when cells receive more damage than they can easily repair.

In women, smoking has been linked to lower ovarian reserve and changes in egg quality. In men, it has been linked to changes in the number, movement, shape and genetic material of sperm. In both cases, how much and for how long you smoke matters.

How much does the risk increase? A review of studies published in Human Reproduction found that women who smoke are about 60% more likely to experience infertility than those who do not. This does not mean that fertility drops by 60%; it means that the likelihood of having difficulty conceiving increases.

If you smoke or used to smoke and want to know how your fertility is today, a complete fertility workup is the best starting point, for you and for your partner if you have one.

Which substances in cigarettes can affect fertility?

Besides nicotine, these are some of the substances in smoke that have been studied most for their relationship with reproductive health:

• Nicotine: can reduce blood flow to the reproductive organs.
• Cadmium and lead: heavy metals that have been found accumulated in the fluid surrounding the eggs and in testicular tissue.
• Carbon monoxide: takes the place of oxygen in the blood, so less oxygen reaches the tissues.
• Polycyclic aromatic hydrocarbons: compounds formed when tobacco burns that have been linked to a faster loss of follicles in the ovary.

Smoking in Mexico: a factor you can change

In Mexico, about 1 in 5 adults smokes. According to ENSANUT Continua 2022, 19.5% of adults smoke, and the figure rises to 24.5% between the ages of 20 and 39, precisely the stage when many people are trying to get pregnant.

In our consultations, smoking is almost never the main reason for the visit. It usually comes up during the fertility assessment, when someone mentions that they smoke a little, that they used to smoke, or that their partner is the one who smokes. That is why we always ask about it, for both partners and without judgment.

Smoking and female fertility

Smoking can play a role at different moments of the reproductive process, from egg development to its journey through the fallopian tube and the implantation of the embryo.

The ovary and the eggs

Substances from cigarettes can reach the ovary and alter the environment where eggs grow and mature. Studies have found lower levels of anti-Müllerian hormone in women who smoke. In some studies, the difference has been almost half. This hormone helps estimate ovarian reserve, but it does not measure egg quality.

Tobacco has also been linked to changes in the cells that surround the egg and to alterations in its genetic material. In addition, women who smoke may reach menopause between 1 and 4 years earlier than those who do not.

The fallopian tubes can also be affected

After ovulation, the egg moves into a fallopian tube. Inside it there are microscopic structures called cilia that help transport it. If fertilization occurs, they also help the embryo travel toward the uterus.

Tobacco smoke can disrupt this movement. That is why smoking has been linked to a higher risk of ectopic pregnancy, when the pregnancy begins to develop outside the uterus. Studies have found that the risk can range from about double to more than triple in women who smoke.

The uterus and implantation

When the embryo reaches the uterus, it needs to implant. Smoking has been linked to changes in uterine blood flow and in the environment where this process takes place. This can make the conditions for the pregnancy to continue less favorable.

This does not mean that a woman who smokes cannot get pregnant. It means that tobacco can play a role at several stages: ovarian function, egg quality, the fallopian tubes and implantation.

Smoking and male fertility

Substances from cigarettes also reach the testicles and can increase oxidative stress while sperm are being formed. Their effects can show up in a semen analysis and also in characteristics that this test does not usually measure.

Sperm count, motility and morphology

A semen analysis looks at, among other things, how many sperm there are, how well they move and how many have a normal shape.

In a study of more than 1,900 men with infertility, smoking was associated with lower sperm concentration or lower motility. The changes were more evident among those who smoked more cigarettes.

This does not mean that every man who smokes has an abnormal semen analysis, but smoking can add a factor that affects semen quality.

Sperm DNA

Each sperm carries genetic material. Oxidative stress can promote small breaks in that DNA, known as sperm DNA fragmentation.

Studies that pooled data from 190 investigations identified smoking among the lifestyle factors associated with higher fragmentation. That is why a sperm can look normal and still have changes in its genetic material.

Sexual function

Cigarettes also damage blood vessels and can make it harder for enough blood to reach the penis during an erection. In a study of more than 6,700 men, almost 1 in 3 current smokers reported erection problems. Those who had quit smoking showed better results than those who kept smoking.

Does a man's smoking delay pregnancy?

For years, this conversation focused almost exclusively on women, but men's smoking matters too. In a study that followed couples trying to conceive, the man smoking was associated with a longer time to pregnancy, and that time was longer when both partners smoked.

It is worth being precise here. The American Society for Reproductive Medicine (ASRM) notes that it has not yet been shown that smoking directly causes male infertility, although the changes in semen are well documented. It also describes a higher risk of pregnancy loss when the man smokes.

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Vaping and fertility

E-cigarettes are often perceived as less harmful, but we cannot consider them a safe alternative for fertility. Their aerosol is not just water vapor. It can contain nicotine, flavorings and small metal particles that enter the body.

In women, studies have linked vaping to possible changes in ovarian function, follicle development and implantation. However, data in humans are still limited. As of 2026, only 5 clinical studies in women had been identified.

Possible changes have also been observed in men in sperm production and movement. Having less information does not mean that vaping is safe. It means that we still need more studies to understand its real impact.

The ASRM agrees: the available data do not support e-cigarettes as a safe substitute for traditional cigarettes for people trying to conceive. Switching devices does not eliminate exposure to nicotine.

What does the law say about vaping in Mexico?

In Mexico, a constitutional reform published in January 2025 prohibits activities related to e-cigarettes and vapes, and since January 16, 2026, the reform to the General Health Law that penalizes their production, distribution and sale has been in force. Even so, their use is still common, especially among young people. If you vape and are trying to get pregnant, the medical recommendation is the same with or without a ban: the best thing for your fertility is to stop.

Does smoking marijuana affect fertility?

If you are wondering does smoking marijuana affect fertility?, the honest answer is that there is more evidence in men than in women. In men, marijuana use has been linked to lower testosterone, lower sex drive and lower sperm motility, especially with frequent use.

In women, studies on marijuana and fertility do not yet agree: some find effects on the menstrual cycle or on assisted reproduction outcomes and others do not. That is why, while you are trying to get pregnant, the ASRM recommends reducing or stopping its use, for you and for your partner.

Secondhand smoke: other people's smoke counts too

When someone smokes near us, part of the smoke can be inhaled by the people around them. This is known as passive smoking or secondhand smoke.

Cotinine, a substance that indicates nicotine exposure, has even been found in the fluid surrounding the eggs of women who did not smoke but were exposed to smoke.

In a study of more than 3,300 women who did not smoke, greater exposure to environmental smoke was associated with a higher history of infertility. This does not mean that being occasionally near someone who smokes causes infertility. The main concern is repeated exposure at home, in the car or at work.

What if I only smoke once in a while?

Smoking less means lower exposure, but there is no amount of smoking we can recommend as safe for fertility. In addition, the effect can build up over time. If you are trying to get pregnant, cutting down helps, but the goal should be to quit.

Smoking during fertility treatment

A fertility treatment can help at different stages of the reproductive process, but it does not completely eliminate the effects that smoking can have on eggs or sperm.

In treatments such as timed intercourse and insemination, pregnancy still depends on the egg and the sperm being able to meet. In one insemination study, pregnancy was achieved in about 6 out of every 100 cycles when the man smoked, compared with 11 out of every 100 when he did not.

In in vitro fertilization, studies that analyzed more than 16,000 women found fewer pregnancies and births among those who smoked. On average, about 1 fewer egg was also retrieved during egg retrieval. However, not all studies find the same effect size.

Smoking is only one of many factors that can influence a treatment. Age, ovarian reserve, the cause of infertility and semen characteristics also matter.

If you want to understand how results change with age and other factors, you can review what the success rates of fertility treatments show.

None of this is a reason not to try. It is information to help you choose the best time to start and to begin treatment in better condition. And since each cycle is a significant investment, starting in better condition also helps you make the most of it; if you are weighing your options, here you can check the ranges for the cost of IVF in Mexico.

Fertility preservation

The same matters if you are thinking about freezing eggs or sperm. Exposure to tobacco can affect the cells we want to preserve, so it is worth talking about this habit before starting the process.

The same applies if your plan is to freeze embryos during an IVF cycle: the quality of the eggs and sperm that form them is the starting point.

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Smoking and pregnancy: complications worth knowing about

Before going on, an important clarification: what follows describes the risks of smoking during pregnancy. If you have already quit, this section is not about you.

Smoking during pregnancy has been linked to a higher risk of complications such as miscarriage, ectopic pregnancy, placental problems (placenta previa or placental abruption), preterm birth and low birth weight. None of these complications is automatic or inevitable: they are risks that increase, not certainties. That is why quitting before pregnancy is one of the best decisions for you and your baby.

What can change in your fertility when you quit smoking?

Quitting prevents ongoing daily exposure to smoke, although it cannot erase what happened in the past. Improvement also does not happen the same way in women and men.

In men, sperm are produced continuously and take about 3 months to fully form. Studies have found improvements in sperm concentration and total sperm count about 3 months after quitting. Other follow-up studies have observed additional changes up to 6 months.

In women, the ovaries do not produce new eggs. Follicles that have already been lost cannot be recovered. However, quitting prevents the exposure from continuing. There is no exact number of months after which we can say that ovarian reserve or egg quality has recovered.

This does not mean that quitting has little value for a woman. Stopping removes an ongoing exposure and also brings important health benefits before and during a future pregnancy.

Benefits of quitting smoking if you are trying to get pregnant

These are some of the changes that have been observed after quitting:

• Semen quality can improve in terms of sperm count and motility.
• Blood circulation improves, including to the uterus, ovaries and testicles.
• Exposure of eggs and sperm to toxic substances before a treatment is reduced.
• The risk of complications during pregnancy decreases.

What determines how much things improve?

Not everyone improves at the same pace. These factors matter most:

1. How many cigarettes you smoked a day.
2. How many years you smoked.
3. Your age when you quit.
4. Your general health and other habits.
5. Whether you are still exposed to other people's smoke.

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If you are trying to get pregnant and you smoke

You do not need to wait for an abnormal test result to bring it up. If you or your partner smoke, mention it to your medical team from the initial assessment.

It is also not advisable to automatically switch from cigarettes to vaping thinking it is a safe option. If quitting is hard, there are strategies and professional support that can make the process easier.

In Mexico, the Línea de la Vida offers free guidance on quitting tobacco at 800 911 2000, 24 hours a day.

How long before trying to conceive should you quit smoking?

If the man is the one who smokes, ideally he should quit at least 3 months before trying to conceive or starting a treatment. That is how long it takes for a complete new generation of sperm to form. For women there is no exact figure: the sooner you stop, the sooner the exposure ends.

How we approach it at Avida Fertility

At Avida Fertility, our fertility clinic in Mexico City, we talk about smoking from the first assessment, without lecturing. We ask both partners about cigarettes, vaping and marijuana when applicable, because each person's habit influences the eggs or sperm they contribute.

With that information, our medical team decides with you whether it makes sense to adjust when treatment starts, order tests such as a semen analysis or anti-Müllerian hormone, or move forward without changes. The decision is made with your results and your history in hand, and from the start you can see the reference prices for treatments. Avida Fertility holds COFEPRIS permit 253300201A1949.

Where can you find help to quit smoking in Mexico?

Línea de la Vida is run by the National Commission for Mental Health and Addictions (CONASAMA), it is free and you do not need an appointment to call. There are also specialized clinics, such as the one at the National Institute of Respiratory Diseases (INER). Seeking professional support increases the chances of success compared with relying on willpower alone.

Your path to a family, whatever it looks like

The effect of smoking on eggs and sperm matters in every kind of family: whether you want to be a single mother by choice, are building a family with your partner through the ROPA method, or are seeking single fatherhood. In every case, the habits of whoever contributes the eggs or sperm are part of the assessment.

When should you seek a fertility assessment?

It makes sense to schedule an assessment if:

1. You have been trying to get pregnant for more than 12 months, or more than 6 months if you are over 35.
2. You or your partner smoke and are about to start a fertility treatment.
3. You want to preserve your fertility for later, whether to freeze eggs or freeze sperm.
4. You have had pregnancy losses and one of the partners smokes.

There is no artificial rush here. There is information that is better to have before, not after.

In summary

Smoking can affect fertility in both women and men, and its effects are not limited to a single organ. It can be linked to changes in eggs, sperm, the fallopian tubes and other processes needed to achieve a pregnancy.

Smoking does not mean that pregnancy is impossible. Quitting can reduce an exposure that we can actually change and, in some respects, allow improvements over time.