Cannabis: Preconception, pregnancy, and breastfeeding

I am thinking of becoming pregnant, should I avoid cannabis?

Yes. If you are planning on becoming pregnant you should avoid cannabis. Cannabis can affect your ability to become pregnant. Heavy cannabis use is linked to changes in menstrual cycles in women and lower sperm quality in men [1]. Women who use cannabis and are planning on becoming pregnant should speak to their health care provider about the risks of cannabis use before becoming pregnant. If you are already pregnant, talk to your health care provider.

For more information, read Best Start’s Risks of Cannabis on Fertility, Pregnancy, Breastfeeding, and Parenting (PDF).

If I am pregnant and smoke cannabis, can it hurt my unborn baby?

Pregnant women should not use cannabis in any form during pregnancy. When cannabis is used during pregnancy, the toxins (such as THC) are carried from the mother’s blood to her unborn baby. Smoking cannabis while pregnant also reduces the oxygen supply to the baby. Using cannabis while pregnant can cause low birth weight, which means the baby is born too small. Use can also cause long-term developmental effects as the baby grows such as problems with behaviour, learning, and an increased risk for future substance use. [1] The safest choice is to not use cannabis while pregnant.

For more information, read Best Start’s Risks of Cannabis on Fertility, Pregnancy, Breastfeeding, and Parenting (PDF).

Can I use cannabis during pregnancy to help with morning sickness?

Pregnant women should not use cannabis in any form during pregnancy. Women who experience morning sickness (nausea and vomiting) during their pregnancy should speak with their health care provider about alternative safe treatment options. [1]

Can I use cannabis if I breastfeed?

Breastfeeding mothers should speak to their healthcare provider about the risks of cannabis. Breastfeeding mothers should continue to breastfeed their baby, as there is not enough research to stop breastfeeding if using cannabis. If you choose to continue breastfeeding, use cannabis in moderation and breastfeed your baby before use. If smoking or vaping, wash your hands and change your clothing, as it may contain harmful chemicals from the smoke or vapor. If a parent is impaired by cannabis, their ability to recognize a baby’s hunger cues and to make responsible decisions about an infant’s needs and safety can be affected.

1 Eastern Ontario Health Unit, “Cannabis Summary,” 2018.

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This item was last modified on October 15, 2018