I recently had a 28 year old pregnant patient ask me about the potential effects of cannabis use on her pregnancy.  She had been using cannabis to treat ongoing migraine headaches with great results.    Because I very rarely work with pregnant women as part of my professional practice I had to hit the books and look for what research is out there on how cannabis affects the pregnancy, neonatal growth and the future development of the child.   Here is a summary of what I found.

In 1992, self reported cannabis use during pregnancy was 2.9% of pregnant women.  However some studies found use to be between 10-16% in middle class samples and 23-30% in inner-city populations.

The major study that I found was the Ottawa Prenatal Prospective Study (OPPS) which looked at cannabis use in 682 women in Ottawa Canada.

Studies during pregnancy are obviously limited by the small amount of people but this is what they found thus far (keep in my we often in medicine think medications are safe only to find out that they are in fact dangerous)

Cannabis’ impact on the overall course of pregnancy:

- reduction in gestational age by 1 week; increase in the frequency of contractions. Possible association with pre-term delivery. No physical abnormalities were found at birth.  Heavy use was associated with ocular hypertention and severe epicanthus.

-low protein diets made the adverse effects of cannabis more pronounced.

Cannabis’ impact on growth and neonatal and infant behavior:

-infants have shown to have smaller head circumference.   Visual habituation is affected.   Prolonged startle response and resting tremors similar to patients undergoing opioid withdrawal.

Cannabis’ impact on adolescents:

-decrease in the ability to accomplish goal oriented tasks.

Based on the clinical research that has been completed I would strongly advise against medicating with cannabis during pregnancy.