Effects of caffeine, alcohol and smoking on reproductive outcomesDownload the PDF (2 MB)
Some lifestyle behaviours are known to affect fertility, pregnancy health and the health of the baby at birth and in adulthood. Here is what you need to know about how caffeine, alcohol and smoking affect fertility and reproductive outcomes.
Caffeine is a stimulant present in coffee, tea, energy drinks, some soft drinks, and chocolate. There is no clear evidence that caffeine affects fertility but some studies indicate that women who consume large amounts of caffeine take longer to conceive and may have a higher risk of miscarriage. To be on the safe side it is recommended that women trying to conceive and those who are pregnant limit their daily intake of caffeine to 200 mg per day (approximately two cups of coffee). In men there is no evidence that caffeine affects their fertility.
Alcohol can reduce both male and female fertility but it is not clear what levels are a risk. While it is not established exactly how alcohol impairs female fertility, research shows that even drinking lightly can reduce the likelihood of conception. In men alcohol can impair fertility because it can cause impotence, reduce libido and affect sperm quality.
It is not clear what effect drinking small amounts of alcohol can have on unborn babies but it is well known that high alcohol consumption can be harmful. The more you drink the higher the risk for the unborn baby. Binge drinking (more than six standard drinks on one occasion) can cause miscarriage, stillbirth, premature birth, small birth weight, and Foetal Alcohol Spectrum Disorder (FASD).
For women who are pregnant or planning a pregnancy, not drinking is the safest option. If you decide to drink while you are pregnant it is important to limit it to one or two standard drinks once or twice per week.
Cigarette smoke contains thousands of harmful chemicals that affect all parts of the body, including the reproductive organs. These chemicals can cause damage to eggs and sperm which affect the health of a future child. To avoid this you should stop smoking at least a few months before trying to conceive.
Female and male smokers are more likely than non-smokers to be infertile and women who smoke are more likely to experience early menopause (before age 45). Secondhand smoke is almost as damaging as smoking and women who are exposed to secondhand smoke take longer to conceive than women who are not.
Women who smoke in pregnancy are more likely than non-smokers to experience miscarriage and their babies have increased risk of low birth weight, being born prematurely and having birth defects. Heavy smoking (>20 cigarettes per day) by fathers at the time of conception increases the child’s risk of childhood leukemia.
The good news is that the effects of smoking on eggs and sperm and fertility are reversible. Whether it’s the male or the female partner (or both) who smokes, quitting will increase the chance of conceiving and having a healthy baby. Also, quitting smoking more than 10 years before menopause reduces the risk of early menopause considerably.
There is no safe limit for smoking, the only way to protect yourself and your unborn baby from harm is to quit. But, quitting can be difficult and you may need support. Speak to your doctor for advice and information about available resources.