By: Dr. Kara Ehlers
Did you know that up to 13% of infertility might be caused by smoking? As a Reproductive Endocrinologist and Infertility specialist, I want my patients to be as healthy as possible prior to attempting pregnancy. While most people are well aware smoking can lead to cancer, lung disease, and heart disease, they are not aware of the significant impact smoking has on fertility.
Below are common questions about smoking and fertility health.
How does smoking affect a woman’s fertility?
We know smoking and even second-hand smoke can have a huge impact on fertility in women. Smoking is associated with miscarriage, ectopic pregnancy, infertility, and early menopause. In a study published in Fertility and Sterility in 2000 by Hull and associates, data from nearly 15,000 pregnancies were evaluated. In their study, women who smoked experienced infertility (inability to conceive within 12 months of attempting pregnancy) 54% more often compared to nonsmokers. Even people who only had exposure to secondhand smoke had significantly lower pregnancy rates.
Women are born with all of the eggs they are ever going to have, which means that the eggs are exposed to everything the woman is exposed to throughout her lifetime. Cigarette smoke contains toxic reactive oxygen species, which can damage the delicate egg. When the egg is damaged, it can increase the risk of miscarriage if it is fertilized, but it can also increase the rate of egg loss. When more eggs are lost earlier in life, there are fewer eggs available and it is more difficult to get pregnant which can make it especially difficult in the later reproductive years (late 30s and early 40s).
How does smoking affect a man’s fertility?
While the impact of male smoking on fertility is not as established as with female infertility, there does seem to be a reduction in many sperm parameters including sperm concentration and morphology (shape of the sperm). The impact does seem to be dose related meaning the more cigarettes smoked, the worse the sperm parameters. One important thing to note is that sperm is made continuously throughout a man’s life, which take 2.5-3 months to mature. So if a man quits smoking, his sperm parameters should return to the same levels as a nonsmoker after that time period.
How does smoking affect fertility treatment success?
Multiple studies have also looked at how smoking affects IVF success. When combining the results of all of these studies, it suggests that smokers require almost twice the number of IVF cycles to conceive compared with nonsmokers. Klonoff-Cohen et al. found that smoking at any point in a woman’s life both doubled her risk of not conceiving with IVF and increased her risk of unsuccessful IVF by 9% for every year she smoked.
Smokers undergoing fertility treatment are less likely to respond to the medications, so they require higher doses of medications-which translates to higher costs. Smokers also have fewer eggs retrieved, more cycles where no eggs fertilize, and a higher number of cancelled IVF cycles compared to nonsmokers. The negative effects of smoking on IVF success seem to become worse as a woman ages.
Smoking is also associated with an increased risk of miscarriage in both natural cycles and cycles with fertility treatment, as well as an increased risk of ectopic pregnancy (pregnancy outside the uterus). Nicotine seems to be the main toxic component in tobacco as smokeless tobacco is also associated with an increased risk of miscarriage. Similarly, while there is less evidence surrounding e-cigarettes, they likely carry similar risks and should be avoided during fertility treatment and pregnancy.
If I (we) stop smoking, will it improve my (our) fertility health?
Unfortunately, not all of the damage done by smoking is reversible; however, future damage can be prevented. There is also evidence that pregnancy rates improve within a year of smoking cessation.
How does smoking during pregnancy affect my baby?
According to the U.S. Department of Health and Human Services, over 1,000 infant deaths each year are a result of smoking during pregnancy. There is also an increased risk of birth defects. Women who smoke are more likely to give birth to premature and low birth weight infants, and the infants may have to stay in the hospital for a prolonged period of time. Children exposed to smoke or secondhand smoke during pregnancy are also at increased risk of developing learning problems and attention-deficit/hyperactivity disorder (ADHD).
Exposure to maternal smoking or secondhand smoke is thought to have a big impact on brain development. Children of women who smoked one pack of cigarettes per day during pregnancy have lower IQ scores than children of nonsmoking mothers. They are also at risk of developing reading deficits and deficits in math and visuospatial reasoning.
There is even evidence that men whose mothers smoked during pregnancy have lower sperm counts than men with nonsmoking mothers.
How does smoking after pregnancy affect my infant/child?
Secondhand smoke is a huge health risk for infants and children. There are more than 7,000 chemicals in secondhand smoke with hundreds of those chemicals being toxic and even cancer causing. Asthma, respiratory infections, tooth decay, ear infections, and sudden infant death syndrome (SIDS) are all linked to secondhand smoke. It also takes children of smokers longer to get over colds than children of nonsmokers.
During the first year of life, infants whose mothers smoke are 50% more likely to be hospitalized for a respiratory infection than infants of nonsmokers and that risk goes up to 95% higher if the mother smokes while feeding her infant. It is estimated that 7,500-15,000 infants are hospitalized each year for respiratory infections linked to secondhand smoke exposure.
The lungs of children who breathe in secondhand smoke grow less than their peers, which predisposes them to conditions like bronchitis and pneumonia. Because they get sick more often, they miss more school, and are less likely to finish high school and go to college than children who are not exposed to secondhand smoke. Children of smokers are also more likely to smoke themselves.
Finally, secondhand smoke also increases the risk of developing metabolic syndrome, which increases risk of heart disease, stroke, and diabetes.
How do I quit smoking?
There are many ways to quit smoking and what works for one person is not necessarily what will work for everyone. I recommend to first make a list of all of the reasons you want to quit smoking. Keep that list handy for reference whenever you feel the urge to smoke.
Set a quit date in the future, but not too far in the future. During the time before your quit date, try to stop smoking in your house and in your car. Once you quit, you will become increasingly aware of thirdhand smoke (the smoke that lingers in the air, on clothes/furniture, etc). On your quit date, get rid of all smoking paraphernalia including lighters, ashtrays, and of course cigarettes.
Quitting cold turkey is great, but not everyone can do it. There are over the counter nicotine supplements to help you quit as well as prescription medications. Talk to your doctor to discuss what options may be right for you. There are also many support groups available online and in person. Some health insurance companies even offer incentives on insurance premiums for current smokers who attend support group meetings in an attempt to quit smoking.
The most important thing is not to give up if you are not successful the first time. It can often take people two, three, maybe even 20 times attempting to quit before they finally quit for good. Celebrate every day you made it without smoking and challenge yourself to try again.
If you are a smoker or former smoker and would like to meet with a Reproductive Endocrinologist and Infertility specialist to discuss your fertility, contact us to schedule a consultation.
Klonoff-Cohen H, Natarajan L, Marrs R, Yee B. Effects of female and male smoking on success rates of IVF and gamete intra-fallopian transfer. Hum Reprod 2001;16:1389–90.
Hull M, North K, Taylor H, Farrow A, Ford W. Delayed conception and active and passive smoking. F&S 2000;74(4):725-733