The placenta is the vital organ in your womb that is responsible for exchanging oxygen, nutrients, and waste products with your baby. Marijuana can cross the placenta, meaning that it is capable of reaching your baby’s bloodstream while you are still pregnant.
Several studies have shown that women who use marijuana during pregnancy give birth to babies with altered developmental patterns. For example, infants exposed to marijuana in the womb are more likely to have low birth weight, which is associated with higher chances of future health problems including diabetes, heart disease, and high blood pressure (Gunn et al, BMJ Open, 2016). Additionally, these infants are more likely to require care in the neonatal intensive care following birth versus babies that were not exposed to marijuana during pregnancy, indicating a higher risk of pregnancy complications (Gunn et al, BMJ Open, 2016).
Studies show similar findings outside of humans, as well. In animal models, high doses of marijuana was associated with growth retardation and malformations in offspring, indicating that marijuana may impact key developmental events that allow for normal body shapes and functions (Hall and Degenhardt, Lancet, 2009). Although the mechanism behind this is poorly understood, research is ongoing and it’s safe to say that marijuana has real impacts on babies’ development during pregnancy.