Researchers from Ecole Polytechnique de l’Université de Nice, in Biot, France reviewed the evidence and mince no words in their conclusions.

Here’s what we know.

  • The active substance of cannabis is the delta 9 tetrahydrocannabinol (THC).
  • Some studies conclude that it could decrease motor development of the child at one year of age.

The bottom line?

The authors recommend, “Cannabis use… must be contraindicated during breastfeeding.”

Furthermore, “Mothers who use cannabis must stop breastfeeding, or ask for medical assistance to stop cannabis use in order to provide her baby with all the benefits of human milk.”

But what about smoking weed during pregnancy?

Several years ago, researchers from Erasmus Medical Center in Rotterdam, The Netherlands reviewed the evidence related to prenatal exposure to cannabis. They concluded that its use is “related to some common neurobehavioral and cognitive outcomes, including symptoms of ADHD (inattention, impulsivity), increased externalizing behavior, decreased general cognitive functioning, and deficits in learning and memory tasks.

One more thing to consider. Marijuana can be “cut” with other substances and expose the fetus to other potentially harmful substances.

Starting from conception through breastfeeding, it’s a bad idea for moms to smoke pot.

2/5/10 21:04 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.