Cannabis and Pregnancy

Research shows that harmful outcomes for children exposed to cannabis during pregnancy are most often seen with women who use cannabis often during pregnancy and throughout the entire pregnancy. Less is known about the potential harms of low to moderate use during pregnancy. Until more is known, it is safest for a woman who is pregnant, or who might become pregnant, to not use cannabis. If you or someone you know needs help quitting, call the HealthLine at 811 for advice and support.


Cannabis comes from the cannabis plant. Cannabis can be inhaled (smoked), swallowed (e.g., in food and drinks), placed under the tongue (e.g., strips and sprays), or applied on the skin (e.g., oils and creams).

Cannabis contains hundreds of chemicals. The most researched of these is tetrahydrocannabinol (THC). THC is the chemical in cannabis that makes people feel “high”. The strength of the cannabis product depends on the level of THC in the product. The highest THC levels are found in hash oil, followed by hashish (resin), and marijuana (dried leaves/flowers). Cannabidiol (CBD) is another chemical in cannabis. Unlike THC, it does not make people feel “high”.

Short-term effects of using cannabis can include:

  • Euphoria (feeling “high”)
  • Feeling relaxed
  • Feeling hungrier than usual
  • Rapid, strong, or irregular heartbeat
  • Anxiety
  • Problems paying attention
  • Problems with memory
  • Difficulty making decisions

Long-term effects of using cannabis can include:

  • Addiction (psychological and physiological dependence)
  • Problems with lungs and airways (e.g., lung infections; a chronic, long-term cough; bronchitis)
  • Problems with memory, attention, learning, and problem-solving
  • Increased risk of depression and anxiety

Cannabis is now legal in Canada (as of October 17th), but this does not necessarily mean it is safe to use. It is important that people understand the negative effects that cannabis can have before, during, and after pregnancy.

  • Cannabis use may negatively impact fertility (make it harder to get pregnant).
  • Cannabis use during pregnancy may harm the developing baby (e.g., baby may be smaller than normal, born too early, or have birth defects).
  • Children who are exposed to cannabis during pregnancy (in the womb) may experience negative effects in childhood and adolescence (e.g., poorer memory and verbal skills; behavioural changes, such as increased rates of impulsivity and hyperactivity).
  • Infants and children who are exposed to cannabis through breast milk may experience negative effects, such as lethargy (lack of energy), poor feeding habits, and slower motor development (the ability to move).

There are serious, potential risks for young children whose parents use cannabis. These risks include:

  • Poisoning
  • Motor vehicle crashes if parents drive while “high”
  • Risks from second-hand smoke

Children are at risk of poisoning if they eat items containing cannabis. Overdoses of cannabis in children are most common when children mistake foods containing cannabis for regular foods (e.g., gummy bears, brownies, lollipops). Smaller children are at higher risk of poisoning because of their size and weight. It is important that parents keep cannabis out of the sight and reach of children, if possible in a locked cabinet.

Parents can also put their children in danger if they are “high” while driving. It is also important that parents do not smoke cannabis around their children, since second-hand cannabis smoke may cause some of the same health problems for children as second-hand tobacco smoke.

Related Resource

For more information about the potential effects of cannabis use before, during, and after pregnancy, see the resource titled Cannabis Use in the Childbearing Years: An Evidence Summary for Healthcare Providers

Full article