In a new study recently published in the proceedings of the National Academy of Sciences, researchers found that children of women who used marijuana during pregnancy or while breastfeeding were at a higher risk for negative psychiatric outcomes. The investigators examined 322 pairs of mothers and children as part of a broader research project on how pregnancy is impacted by stress. Hair samples were collected from the children when they were between 3 and 6 years old to measure hormone levels and researchers also examined placental tissue collected at time of birth.

In the analysis, children prenatally exposed to THC had higher levels of the stress hormone cortisol and were twice as likely as non-exposed children to develop aggression, anxiety, and hyperactivity. Furthermore, researchers found diminished expression of immune-activating cells in the placental tissue of women who used marijuana during pregnancy, suggesting that some degree of immunosuppression may occur in exposed children. It is also worth mentioning that in the analysis, investigators were able to account for other factors that could have explained the results such as parental education level, ethnicity, and age etc.

Drug Free America Foundation Epidemiologist Dr. Sharif Mohr commented, “How many more studies need to be done before something is done about the staggering number of women who use marijuana during pregnancy and think that it is safe to do so. There is no safe level of marijuana use during pregnancy, period.”

Source: Rompala G, Nomura Y, Hurd YL. Maternal cannabis use is associated with suppression of immune gene networks in placenta and increased anxiety phenotypes in offspring. Proc Natl Acad Sci U S A. 2021 Nov 23;118(47):