The U.S. Surgeon General issued a new advisory Thursday warning against cannabis use by youth and pregnant women.
In Colorado in 2017, 19.4 percent of high school students use marijuana. That's the most recent data available. Just over 7 percent of mothers reported using marijuana during pregnancy during 2017.
Surgeon General Jerome Adams' advisory said increased availability and potency of marijuana is endangering the country's children because of the documented damage it can do to developing brains.
"We have seen a big jump in THC potency here in Colorado, particularly for concentrate," said Jessica Neuwirth with the Colorado Department of Public Health and Environment's retail marijuana education project. "What that means is a little blurrier. There's not a ton of evidence that supports that increased potency is going to increase any adverse health effects. There are some unknowns about the potential health impact of that."
The THC concentration in cultivated marijuana plants has tripled from 4 percent in 1995 to 12 percent in 2014, according to HHS data. Average THC concentration in flowers sold in Colorado was 17 percent in 2017, according to CDPHE data. Concentrated products like dabs or waxes have an average of 62 percent THC concentration.
"Recent increases in access to marijuana and in its potency, along with misperceptions of safety of marijuana endanger our most precious resource, our nation’s youth," Adams said in his advisory. "This ain't your mother's marijuana."
Pregnant women use marijuana more than any other illicit drugs, according to the U.S. Department of Health and Human Services. It's also the most-used drug by adolescents behind alcohol.
The Colorado Pregnancy Risk Assessment Monitoring System data show that marijuana use during pregnancy is associated with a 50 percent increase in the risk for low birth weight. The human brain is still developing into a person's mid-20s. HHS reports frequent marijuana use during adolescence can impair learning and change areas of the brains that manage attention, memory, decision-making and motivation.
Neuwirth said there were no significant increases in either adolescent or maternal marijuana use after the legalization of recreational marijuana in 2012.
She said CDPHE is working to keep those rates from rising by collecting data on marijuana use and with educational marketing campaigns targeted at youth, parents and teachers.