Marijuana use continues to increase in the United States, including use by women who are pregnant. It is the most commonly used illicit drug used during pregnancy. A national survey involving over 200,000 women between the ages of 18 and 44, the use of marijuana during pregnancy increased by over 60 percent between 2002 to 2014.1
Although there is limited information regarding the effects on the babies of mothers who smoke marijuana in pregnancy, there does not seem to be an increased risk of premature labor and birth. There is also no evidence that marijuana use causes birth defects. Some research studies have shown that babies born to mothers that smoke marijuana on a regular basis are smaller at birth.2
So far, what research has shown is that children born to mothers that smoked marijuana may have:
- Lower scores in verbal reasoning, especially if the mother smoked marijuana during the first trimester of pregnancy.
- Lower scores on tests requiring abilities related to short-term memory, math, and reasoning skills, especially if the mother smoked marijuana during the second trimester.
- Decreased attention spans, impulsive behavior, hyperactivity, anxiety, and depression.
Marijuana also passes through breast milk to infants. Babies that are breastfed by mothers that regularly smoke marijuana have shown a decrease in muscle tone, difficulty sucking, and a delay in motor development at one year of age.
Delta-9-tetrahydrocannabinol (TCH) is the main compound found in marijuana. However, there are over 450 ingredients in marijuana smoke. Many of these ingredients are toxic.
- Chang, G. (2017). Substance misuse in pregnant women. UpToDate. Retrieved from
- Jansson, L. (2016). Infants of mothers with substance use disorder. UpToDate. Retrieved from