It's no secret that smoking is detrimental to your health; so it's probably no surprise that smoking can affect your fertility. Smoking has been linked to an increased risk for many cancers, heart disease, emphysema, and a number of other health problems. The toxins contained in cigarettes take their toll not only on your lungs, but on your entire body's health, including your reproductive system.
Also, because smoking can harm a child prenatally, it's a good idea to quit smoking before you even consider pregnancy. That being said, if you decide not to quit smoking before you start trying to conceive, you may have trouble getting and staying pregnant in the first place.
To get more details on smoking and fertility, read this excerpt from UpToDate -- a trusted electronic reference used by many physicians and patients.
Then, read on for what all of this means for you.
"Approximately 23 percent of American women age 18 or over smoke cigarettes, and up to 13 percent of subfertility [lower fertility] has been attributable to cigarette smoking. Studies of the impact of smoking on fertility have typically analyzed the effects of "cigarettes smoked per day" on fecundability [possibility of conception]. Most series report that fecundability is decreased if the female partner smokes greater than 10 cigarettes per day. Possible mechanisms include tubal changes, cervical changes, damage to gametes, and increase in spontaneous abortion and ectopic pregnancies. In addition, numerous studies linking smoking to early menopause suggest that cigarette smoking causes premature depletion of the ovarian pool of oocytes and premature aging of the ovary by one to four years. Components of cigarette smoke may cause oxidative stress and DNA damage in the ovarian follicle. Ovarian aging is thought to be a major contributor to unexplained infertility.
"These relationships were best illustrated in a meta-analysis including data from almost 11,000 smoking women and 20,000 nonsmokers. Cigarette smoking by the female partner was associated with a statistically significant increase in infertility compared to nonsmokers...Although only observational studies were included, the evidence was compelling because of the consistency of the effect across different study designs, sample sizes, and types of outcome. Others have shown that the time to achieve pregnancy also increases with the number of cigarettes smoked per day."
Infertility and Smoking
Much of the research on smoking has focused on the effect that a particular number of cigarettes has on a woman's fertility. Studies have found that a woman who smokes 10 or more cigarettes per day is likely to experience infertility connected to her smoking habit.
This doesn't mean smoking fewer cigarettes per day would not lead to lowered fertility. But it is clear that smoking 10 or more a day increases your risk of developing problems.
In the studies, smoking was found to specifically be associated with the following fertility problems:
- Problems with the fallopian tubes, including blockages (preventing egg and sperm from meeting) and an increased risk of ectopic pregnancy.
- Cervical changes, specifically an increased risk of developing cervical cancer.
- Damage to the eggs as they develop in the ovaries.
- Increased risk of miscarriage, possibility due to damaged eggs, damage to the developing fetus, or unfavorable changes in the uterine lining, which may make healthy implantation of an embryo less likely.
Smoking and Earlier Menopause
Some studies have shown that smoking can cause not only problems with fertility while you're smoking, but lead to lowered fertility in the future.
While men produce new sperm throughout their lives, women are born with all the eggs they will ever have. Once those eggs are damaged, there's no going back.
Smoking may decrease the total number of eggs a woman has in her ovaries, and cause the ovaries to age prematurely. Toxins in cigarettes may also lead to DNA damage to the ovarian follicles, where the eggs normally develop to maturity. This premature aging of the ovaries and decrease in eggs may lead to earlier menopause, as much as four years earlier than normal.
More Smoking Leads to Longer Time to Conception
Research has also found that the more cigarettes a woman smokes a day, the longer she will take to get pregnant.
According to one study, which looked at just over 4,000 women, after three and a half months of trying to get pregnant, almost 60% of non-smokers had achieved pregnancy. For women who smoked one to ten cigarettes a day, around 50% had achieved pregnancy. And for women who smoked over ten cigarettes per day, only 45% had achieved pregnancy after three and a half months.
If quitting completely does not seem to be in the cards for you, cutting back is still worth trying for.
The Bottom Line
Don't feel that there's no turning back after years of cigarette smoking. While smoking can lead to some long-term fertility damage, studies have also shown that fertility rates can improve after one year of quitting.
Some women may be tempted to keep smoking until they get pregnant. However, it's best for you and your future baby if you quit before you achieve pregnancy. It'll improve your chances of conceiving, be easier on your body, healthier for your baby, and lower the risk of miscarrying the pregnancy before you've even had a chance to give up smoking.
If your partner is also a smoker, it's best to quit together, and there are many good reasons to do so. His secondhand smoke may lower your fertility and threaten your pregnancy, and some studies have found that smoking lowers male fertility as well. This is not to mention the health problems that can arise in babies and children who are exposed to secondhand smoke.
Dropping the habit together will increase your chances of successfully quitting, too.
Want to learn more? See UpToDate's topic, "Optimizing natural fertility in couples planning pregnancy", for additional in-depth, current and unbiased medical information on infertility, including expert physician recommendations.
Olek, Michael J., Gibbons, William E. "Optimizing natural fertility in couples planning pregnancy." UpToDate. Accessed: September 2009.