How do smoking and drinking affect conception?

Drinking a few glasses of wine may help put you in the baby-making mood, but how does drinking affect your chance of conceiving?
Drinking a few glasses of wine may help put you in the baby-making mood, but how does drinking affect your chance of conceiving?

The list of pregnancy dos and don'ts may feel long, with everything from whether or not it's OK to dye your hair, have a cup of coffee or take a bath up for debate. But for millions of women, it's not the dos and don'ts of pregnancy that weigh on their minds; rather it's the dos and don'ts of getting pregnant.

For a healthy woman in her 20s (younger than 27 years old), the chances of conceiving are about 50-50 from month to month. At 30, though, those odds drop, and women only have about a 20 percent chance of conceiving each month. And at 40, the odds of conception drop to just 5 percent each month [sources: American Society for Reproductive Medicine; Hall]. With about 20 percent of American women waiting until after the age of 35 to conceive, and with about 10 percent of women ages 15 to 44 suffering from infertility, tips for boosting the chance of conception each month become ever more valuable as time ticks by.


The quantity and quality of both eggs and sperm are key ingredients in having a healthy baby. At birth, a woman has more than a million eggs. That number dwindles to about 250,000 to 300,000 by the time she reaches puberty. But even with that many eggs down for the count, a woman ovulates about 300 to 500 times during her reproductive years, which is more than enough, right? Right, except that eggs have an expiration date. The body absorbs unused eggs, a degenerative process called follicular atresia.

Men, while long thought to be able to father healthy babies well into their advanced years, should also be aware that they, too, have a ticking clock. It's been found that men may suffer from decreased fertility as they age. They may also face an increase in misshapen and defective sperm. But it's not only age that diminishes our ability to conceive. Lifestyle choices such as smoking and drinking have been found to affect conception, as well.


Tobacco Use Before Conception

Smoking, it has been found, increases the rate at which a woman's eggs become unusable and her risk of early menopause, both of which limit her number of fertile years. According to a study published by the British Medical Association, conception rates drop by as much as 40 percent in female smokers when compared to nonsmokers [source: Andalo]. And in addition to the nearly doubled rate of infertility, women take longer to conceive, and natural conception becomes more difficult. When conception does occur, the likelihood of giving birth to a low-birth weight baby is higher for smokers. Smoking before and during pregnancy also increases miscarriage rates, as smoking increases the chance for an egg to have chromosomal abnormalities.

It takes two to make a baby, though, and a man's health and lifestyle can affect fertility and conception. Smoking is linked to low sperm count, low sperm motility (slow movement) and sperm with damaged DNA -- all three problems reduce the quality of sperm and are known to cause fertility issues. Researchers at the University of Saarland found that men who smoked a minimum of 20 cigarettes every day had lower concentrations of protamines, two proteins found in sperm, than men who didn't smoke at all. These protamines are thought to be an integral part of cell division, and they ensure the correct chromosomal formation during conception. In addition to the number of ways smoking is bad for your health, it's bad during conception because it changes the way DNA is handled.


For the best chance of conceiving and carrying a baby to term, it's a good idea to start a smoking cessation plan. Some health professionals recommend you stop about two to three months before trying to conceive to get the full benefits of quitting.

Keep reading to learn how drinking alcohol affects your chances of becoming pregnant.


Alcohol Use Before Conception

Similar to how smoking affects your ability to become pregnant, drinking alcohol before trying to become pregnant may also have adverse affects on conception. While the effects of alcohol consumption during pregnancy are well known -- the physical, behavioral and cognitive problems known as Fetal Alcohol Spectrum Disorders -- drinking before getting pregnant can also cause problems. Alcohol consumption can lower your chances of conception, and it's also linked with higher chances of miscarriage.

A study published in the British Medical Journal found that women who drank more than 10 alcoholic beverages per week had impaired fertility, and even those women who drank five or fewer drinks per week had a harder time getting pregnant than women who didn't drink at all while trying to conceive [source: Jensen et al].


Alcohol appears to affect estrogen and other reproductive hormones in the body, making monthly cycles longer and anovulatory cycles -- menstrual cycles during which ovulation doesn't occur -- more common. If ovulation doesn't occur, a woman's ovary doesn't release an egg. When this happens, a woman literally can't become pregnant, no matter how hard she tries.

Men who drink alcohol may also suffer from alcohol-related fertility issues such as low sperm count and low sperm motility. What does this mean when you're thinking about getting pregnant? A man's ejaculate contains fewer sperm, and a higher percentage of the available sperm are unable to make the long journey to fertilize a woman's egg.

So what's a couple to do? The best thing is to stop drinking alcohol when you decide to try to get pregnant, and just as with smoking cessation, some health professionals will recommend stopping about two to three months before trying to conceive to get the full benefits.

For more information about how drinking and smoking affect conception, check out the great links on the next page.


Lots More Information

Related Articles

  • American Fertility Association. "Infertility Risk Assessment." 2008. (March 21, 2011)
  • American Pregnancy Association. "Female Fertility Testing." 2007. (March 21, 2011)
  • American Society for Reproductive Medicine. "Age and Fertility: A Guide for Patients." 2003. (March 21, 2011)
  • American Society for Reproductive Medicine. "Patient's Fact Sheet: Smoking and Infertility." November 2003. (March 21, 2011)
  • Andalo, Debbie. "Smoking 'cuts conception success by 40%'." The Guardian. Feb. 11, 2004. (March 21, 2011)
  • Centers for Disease Control and Prevention. "Infertility FAQ's." Dec. 28, 2009. (March 21, 2011)
  • Chan, Amanda. "More evidence ties smoking, decreased fertility." Sept. 8, 2010. (March 21, 2011)
  • Emanuele, Mary Ann et al. "Alcohol's Effects on Female Reproductive Function." The Endowment for Human Development. 2003. (March 21, 2011)
  • European Society of Human Reproduction and Embryology. "Should Obese, Smoking and Alcohol Consuming Women Receive Assisted Reproduction Treatment?" ScienceDaily. Jan. 19, 2010. (March 21, 2011)
  • Hall, Carl T. "Study speeds up biological clocks / Fertility rates dip after women hit 27." San Francisco Gate. April 30, 2002. (March 21, 2011)
  • Human Reproduction Update. "Protamines and male infertility." March 31, 2006. (March 21, 2011)
  • Jenson, Tina Kold et al. "Does moderate alcohol consumption affect fertility? Follow up study among couples planning first pregnancy." British Medical Journal. Aug. 22, 1998. (March 21, 2011)
  • Powell, Kendall. "Age is no barrier …." Nature. Nov. 3, 2004. (March 21, 2011)
  • Rabin, Roni. "It Seems the Fertility Clock Ticks for Men, Too." The New York Times. Feb. 27, 2007. (March 21, 2011)