While scientific research into the effects of cannabis on pregnancy and breastfeeding may not be as comprehensive as research into the effects of alcohol, we do know that cannabis consumption can pose risks for conception, during pregnancy and while breastfeeding. If you (and/or your partner) are consuming cannabis while trying to become pregnant or while pregnant or breastfeeding, it is important to speak with your healthcare provider.
There’s no evidence to suggest that any level of cannabis consumption is safe for those who wish to become pregnant (including non-birthing parents), pregnant people, fetuses and those who are breastfeeding.
Here’s what we know about cannabis, pregnancy and breastfeeding.
Cannabis use while planning a pregnancy
While many people stop using cannabis during and after pregnancy, prospective parents also need to consider how cannabis consumption may affect fertility and conception. Regular cannabis use (defined as weekly or more frequent cannabis use over a period of months to years) can cause changes in both male and female fertility. For more information, consult with your healthcare provider.
Cannabis use while pregnant
While more research is needed to fully understand the effects of cannabis use during pregnancy, experts agree there are potential risks to both the pregnant person and the fetus.
Here’s what we do know, according to Health Canada:
- Cannabis can decrease blood pressure, which can cause dizziness or fainting in pregnant people.
- Those who consume cannabis while pregnant slightly increase their risk of anaemia.
- Cannabis consumption may also increase fatigue, forgetfulness, anxiety or paranoia.
Pregnant people may wonder about using cannabis to treat nausea during their pregnancy. There is no evidence that treating nausea, vomiting or pain during pregnancy with THC or CBD has any beneficial effect. Talk to your healthcare provider about safer alternatives.
Cannabis use during pregnancy also poses risks to the fetus. Chemicals in cannabis, including THC, are carried through the bloodstream and pass onto the fetus. This means that when a pregnant person consumes THC, the fetus will, too. Cannabis use during pregnancy can result in a lower birth weight, which can increase the risk of health complications in childhood.
While further research is needed, evidence suggests that cannabis consumption during pregnancy and breastfeeding may have long-term effects on fetuses and breastfed babies, depending on their exposure. It’s possible that it may affect behaviour, brain development and mental health.
Cannabis use while breastfeeding
Cannabinoids such as THC pass from the blood into breastmilk and then to the baby. In fact, there may be up to eight times more THC in breastmilk than in the mother’s blood. (It is important to note that while THC is stored in fatty tissue, such as the breasts, more research is needed to understand how CBD is stored.) Research suggests that newborns exposed to THC through breastfeeding can experience excessive drowsiness and may have difficulty suckling. They may also have reduced muscular tone.
While “pumping and dumping” is a method people sometimes use when breastmilk may contain alcohol or prescription drugs, this approach does not work for cannabis. That’s because THC is stored in the body’s fat cells and is slowly released back into the bloodstream long after a person stops using cannabis — longer than many other drugs. For those who consume cannabis daily or more frequently, it can take up to 30 days for cannabis to stop showing up in their blood.
While more research is needed to understand all the ways cannabis consumption may affect fertility, pregnancy and breastfeeding, the takeaway is clear: The safest amount of cannabis to use during pre-conception and pregnancy, and while breastfeeding is no cannabis at all. For more information, please contact your healthcare provider.