Thinking about using cannabis before or during pregnancy?

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Organization: Health Canada

Date published: 2018-10-15

Get the current facts about using cannabis for non-medical purposes during pregnancy and the health effects it can cause a growing child. Talk with your health care provider about information on cannabis for medical purposes.

About cannabis

Cannabis is also known as marijuana, weed and pot. It has more than 700 chemical compounds. Hash and hash oil also come from the cannabis plant.

  • Delta-9-tetrahydrocannabinol (THC) is the chemical compound that makes people feel high.
  • THC content in cannabis has increased over the past several years.
  • Cannabidiol (CBD) is another chemical compound known for its therapeutic use for pain, inflammation and anxiety.
  • CBD does not make you feel high.
  • CBD products may contain THC.

Until more is known about the short and long-term effects of cannabis, it is safest to avoid using cannabis when pregnant and breastfeeding.

Risks of using cannabis

Second-hand cannabis smoke can be harmful. It is safest not to smoke or vapourize cannabis at home or in a car.

Using cannabis daily, or almost daily, may have effects that last for several weeks, years or never fully go away, even after stopping use. Some people may have a higher risk of:

  • Developing a mental health problem
  • Having an existing mental health problem worsen
  • Having psychotic episodes

More research is needed to clearly understand all the possible health effects of cannabis use.

Cannabis in foods or drinks can make people feel higher than expected. Because the effects of cannabis are not felt right away but can appear hours later, people may take more cannabis than they had planned.

  • The body has to digest the cannabis before feeling the effects.
  • The signs and symptoms can vary from mild to severe.

Before pregnancy

If thinking about getting pregnant, start prenatal care early. Cannabis use may affect:

  • Ability to get pregnant
  • Menstrual cycle
  • Sperm count and quality

During pregnancy

Cannabis is not recommended to treat morning sickness or for medical purposes during pregnancy. Ask a health care provider about safer options to feel better. To know more, refer to the web link Nausea and Vomiting.

  • The more cannabis is taken during pregnancy, the more it affects the baby’s developing brain.
  • Cannabis use may also affect a mother’s health during and after pregnancy.

There is no known safe amount of cannabis use during pregnancy.

If using cannabis during pregnancy, a newborn has more risk of:

  • Lower birth weight
  • Lower alertness

These risks can lead to health problems for a growing child.

Although cannabis is a natural plant, it doesn’t make it safe during pregnancy.

Risks to a child’s brain development

Use of cannabis during pregnancy may affect a child’s brain development, behaviour and mental health into adolescence and early adulthood. The effects may be permanent. If a mother uses cannabis daily, some of the risks for the child may be:

Age 0 – 3 years:

  • Difficulty calming down
  • Exaggerated startles
  • Sleep problems

Age 3 – 6 years:

  • Poorer memory
  • More impulsive
  • Less attentive
  • Less able to understand and follow instructions

Age 6 – 10 years:

  • More hyperactive and impulsive
  • More difficulty learning
  • Symptoms of depression and anxiety
  • More difficulty making decisions
  • Less attentive

Age 14 – 18 years:

  • Poorer school performance
  • Delinquency problems
  • May try and/or use cannabis earlier
  • Continue to be hyperactive, impulsive and less attentive

Before baby arrives

Talk to your health care provider about breastfeeding.

Cannabis passes into the breast milk. It can be stored in your baby’s fat cells and brain for weeks.

  • Breastfeeding is the healthiest choice for your baby.
  • If you need help to reduce or to stop cannabis use, ask your health care provider about support and services in your region.

If you are unable to stop using cannabis completely, try using less, and less often.

Learn about the effects of cannabis as new information becomes available:

Acknowledgement: The Public Health Agency of Canada would like to thank Best Start Resource Centre for adapting this resource based on their booklet, “Risks of Cannabis on Fertility, Pregnancy, Breastfeeding and Parenting” (2017). We would also like to thank the parents and experts who provided input into the document.

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