Substance use and fertility

The negative impacts of smoking, drinking alcohol, and/or using other substances on women’s fertility are still not fully understood; however, available evidence points to potential negative effects of using all these types of substances on female fertility.

It is never too late to consider reducing or eliminating use of alcohol, tobacco, and/or other substances if you are thinking about getting pregnant. There are many resources available in the community and through your health care provider that can help you quit or manage your use.


While drinking large amounts of caffeine may increase the time it takes to become pregnant, there is no evidence that drinking moderate amounts of caffeine (1 to 2 cups of coffee a day) affects fertility.


The effects of alcohol on women’s fertility are not as well established as its effects during pregnancy. Available evidence shows that heavy alcohol use may negatively affect ovulation, cause periods to become irregular or stop, increase the time it takes to get pregnant, and impair fertility. It is less clear what the effects of light alcohol use are on fertility. If you are planning a pregnancy, reducing or stopping drinking is the safest option to protect your fertility and prevent any unintended alcohol use early in pregnancy when you may not realize you are pregnant.


Smoking is consistently shown to have negative effects on human health, including women’s reproduction. Compared to non-smokers, women who smoke are more likely to have fertility problems, take longer to conceive naturally, and are less likely to conceive with assisted reproductive technologies, such as in vitro fertilization. Frequent exposure to second-hand smoke is almost as dangerous as smoking yourself. Cigarettes contain thousands of chemicals that can harm your reproductive system and oocytes (eggs), affecting a future child’s health and ability to have their own children later in life. Quitting smoking at least a few months before trying to conceive can improve your chances of getting pregnant and having a healthy baby.


Cannabis affects the body through receptors present on cells in many organs. Among these are your reproductive organs, which are involved in fertility and pregnancy. While there is limited evidence that cannabis has a direct effect on your reproductive system and hormones, cannabis use is reported to be high among patients with infertility. Cannabis use can disrupt ovulation and reduce a women’s chance of getting pregnant. There is very little information available regarding how different amounts and ways of consuming cannabis (smoking, vaping, edibles) can affect fertility.


Long-term use of opioids (such as hydromorphone, oxycodone, and fentanyl) can affect a woman’s fertility. Opioids can decrease your production of sex hormones (estrogen, progesterone), leading to abnormal periods, impaired ovulation, and reduced fertility or infertility. Long-term users also have a higher risk of early menopause or premature ovarian failure, where the ovaries stop working before normal menopause. If you use opioids, speak to your health care provider about treatment options that can improve your chances of conceiving and having a healthy baby.

Street drugs

There is very little information available about the relationship between other street drugs and women’s fertility. Street drugs are never safe for use, particularly if you are planning a pregnancy.