Risks of Marijuana Use During Pregnancy

woman smoking marijuana

Ten years ago, it would have been unthinkable: Pregnant women advising each other to smoke marijuana. But now, take a look at just about any pregnancy forum and you’ll find posts on this topic with strong opinions on each side.

For some women, early pregnancy is a grueling time. They go through severe nausea and vomiting for several weeks. The world learned more about this problem as, in the UK, Princess Kate would disappear from view for days at a time during her early pregnancies. She was hospitalized multiple times to prevent damage to her baby due to her inability to hold down food and fluids.

Some women are strong advocates for the use of marijuana during early pregnancy to alleviate nausea and vomiting. But at this most delicate of times, as a baby grows rapidly and develops nerve and brain tissue, it’s vital to know the possible effects of marijuana use before choosing this alternative. Fortunately, we have data on these possible effects available in scientific studies and research.

The THC in Marijuana is Attracted to Fatty Tissues

The primary intoxicating ingredient in marijuana is tetrahydrocannabinol (THC). This drug is lipophilic which means it is attracted to and tends to be stored in fatty tissue. Brain tissue is highly fatty and can act as a “depot” for THC.

fetus of unborn baby

In the first few months of pregnancy, a baby’s brain develops rapidly. If a pregnant woman uses marijuana, she could be bathing her baby’s new brain tissue with THC, as this drug easily passes through the placenta and into the fetus. Could this exposure cause any problems to the brain or other parts of the growing baby’s body?

In Colorado, the Department of Public Health & Environment was charged with the responsibility to study the public effects of marijuana use. In 2014, they published their comprehensive report.

This report notes that THC has the potential to create harm to the developing fetus. There is a risk of birth defects, abnormal growth and most critically, sub-normal brain development.

Many women who use marijuana during pregnancy claim that the babies have turned out fine. This report from Colorado notes, however, that the damage associated with marijuana use may not show up until adolescence. That damage can include decreased academic ability and decreased cognitive function and attention. There’s also evidence that exposure to the chemicals in marijuana may also result in decreased overall growth and lower IQ scores in young children.

This report also noted many other problems that could turn out to be associated with marijuana use, especially when it’s used during early pregnancy, such as low birth weight, preterm delivery, and defects of the brain, spine or spinal cord, but the evidence of these problems is currently incomplete. One of the defects thought to be associated with THC is anencephaly, a severe and usually fatal condition where a baby is born with only part of a brain or none at all.

The Official Conclusion of this Report

In summary, the Colorado Department of Public Health & Environment issued this official statement (in part):

1. Maternal use of marijuana during pregnancy is associated: with negative effects on exposed offspring, including decreased academic ability, cognitive function and attention. These effects may not appear until adolescence.

2. Marijuana use during pregnancy may be associated with an increased risk of heart defects in exposed offspring.

3. Marijuana use during pregnancy may be associated with an increased risk of stillbirth.

4. There is conflicting research on whether or not marijuana used during pregnancy is associated with increased marijuana use in exposed offspring.

5. Marijuana use during pregnancy may be associated with increased depression symptoms and delinquent behaviors in exposed offspring.

6. There are negative effects of marijuana use during pregnancy regardless of when it is used during pregnancy.

What Conclusion Should One Come to?

Certainly, there is more research needed to zero in on the exact effects of THC exposure during pregnancy. Nearly all pregnant women are acutely conscious of the need to protect the health of their growing babies. These effects need to be clarified beyond any reasonable doubt and the information distributed broadly where pregnant women can access it.

In the meantime, as this report concludes, “there are negative effects of marijuana use during pregnancy regardless of when it is used during pregnancy.” Therefore this information should be known to every potential mother and father.



Sue Birkenshaw

Sue has worked in the addiction field with the Narconon network for three decades. She has developed and administered drug prevention programs worldwide and worked with numerous drug rehabilitation centers over the years. Sue is also a fine artist and painter, who enjoys traveling the world which continues to provide unlimited inspiration for her work. You can follow Sue on Twitter, or connect with her on LinkedIn.