For the most part, people know that a pregnant person shouldn’t drink alcohol, but they may wonder if the same is true for marijuana. Marijuana (cannabis) is the most common substance used by pregnant people. Even though marijuana is becoming more socially acceptable, there are no known safe levels of marijuana use during pregnancy and while breastfeeding. 

Why do people use marijuana when pregnant?

Some people stop using marijuana when they learn that they are pregnant while others continue to use it. There are many reasons why pregnant people continue to use it including:   

• Thinking it’s safe and being unaware of the possible risks it poses to the baby 
• Having fun and enjoyment 
• Managing the stresses of daily life  
• Having a partner who uses marijuana 
• Addressing morning sickness including nausea and vomiting 
• Treating pre-pregnancy conditions including mental health, sleeping problems, cramps from periods, chronic pain and migraines  
• As a means of harm reduction, meaning using marijuana instead of alcohol and other drugs that can pose greater risks to the developing baby 

What are the risks to the baby?

Many factors can impact the baby’s health when it comes to marijuana. How much marijuana is used, how often, its potency or strength, the way it’s consumed (e.g., smoked, vaped, eaten), and whether it’s used throughout pregnancy can make a difference.  

While research results investigating the effects of marijuana on pregnancy are sometimes conflicting, some studies raise the following concerns: 

• Lower birth weight 
• Pre-term birth 
• Increased risk of being admitted to intensive care 
• “Withdrawal” symptoms including more startles and tremors as well as sensitivity to light 
• Attention, social and behavioral problems in childhood and teen years 

 

What are the risks to the pregnant person?

Addiction: Continued use of marijuana may result in a person developing Cannabis Use Disorder. This is the medical term for problematic marijuana use and addiction.  To learn more about whether this applies to your loved one read Is Marijuana Addictive?. 

Cannabis Hyperemesis Syndrome: Another concern relates to using marijuana to help with morning sickness. With regular use of marijuana, some pregnant people will develop Cannabis Hyperemesis Syndrome (CHS). CHS is diagnosed when a person has severe stomach pain, nausea and vomiting that can last for 24 to 48 hours. Often relief from CHS symptoms comes from taking hot showers. The only known way to treat it is to stop using marijuana. 

Child Protective Services: For some pregnant people, especially people of color, there may be a concern about criminal justice involvement or reports to child welfare services. This is an issue for pregnant people even in states where marijuana use is legal. In a 2019 study, researchers found that most patients did not discuss their marijuana use with their providers for fear of being reported to child protective services. Those who chose to talk about their use were met with a mix of health messages and threats. 

Anemia: Using marijuana when pregnant increases the odds of having anemia compared to those who do not use it.  A person who is anemic can feel tired, weak, and short of breath. They may also have trouble concentrating and experience a rapid or irregular heartbeat. Left untreated, it can lead to low birth weight, premature weight or maternal death. 

What is important to know about marijuana use while breastfeeding?

Many people also report using marijuana while nursing. Regardless of how a person uses marijuana (e.g., smoked, vaped or edibles) THC, the active ingredient in marijuana that produces a “high”, passes through the milk to the baby.  Marijuana can be found in the milk for a long period of time – as much as 6 weeks after use.  

Studies on the impact of nursing while using marijuana on a baby’s development are conflicting. For example, one study showed that marijuana use while nursing was linked to poorer motor development in infants (e.g., the way babies reach and kick). Another study showed no differences in the babies’ development. Given the conflicting data and uncertainty about infant safety of marijuana use when nursing professional associations encourage people to reduce or stop marijuana use during breastfeeding. 

There is also a concern about secondhand and thirdhand smoke if marijuana is consumed using a joint, blunt, bowl or vape pen. The baby can breathe in the smoke and experience the effects of THC. Babies may also grab objects where the smoke or vapor has settled to put in their mouths.  These objects may carry toxins that can negatively impact babies’ health. 

What can families do to be supportive?

1. Recognize that your loved one may see marijuana as helpful to relieve symptoms and cope.   
2. Share your concerns about the risks to the baby. 
3. Encourage your loved one to discuss their use with a trusted healthcare provider as they may be able to offer guidance and other ways to cope. 
4. If your loved one continues to use marijuana, consider talking to them about ways to reduce the risks. Our guide on harm reduction measures may help.