Kerry Dooley Young
August 29, 2019
The United States surgeon general wants to counter what he calls a "false perception" of the safety of marijuana, emphasizing the risk to a fetus' developing brain — and the growing brains of children and teens — as a result of the more potent forms of the drug often sold today.
"No amount of marijuana use during pregnancy or adolescence is known to be safe," said US Surgeon General Jerome Adams, MD, in a formal advisory today. "Until and unless more is known about the long-term impact, the safest choice for pregnant women and adolescents is not to use marijuana."
But with marijuana now legalized to some degree in more than 30 states, consumers may underestimate the risks of this drug, Adams said. The marijuana sold these days is much stronger than the previous versions, due to rising concentrations of delta-9-tetrahydrocannabinol (THC).
The THC concentration in commonly cultivated marijuana plants rose threefold between 1995 and 2014, from 4% to 12%, Adams said. In some states, the marijuana available in dispensaries has average concentrations of THC between 17.7% and 23.2%. Concentrated products called dabs or waxes may contain 23.7% to 75.9%, according to the advisory.
"This ain't your mother's marijuana," Adams said during a press conference about the advisory.
Use in Pregnancy Rising
Yet, more expectant women are using this drug these days, Adams said, citing data from the National Survey on Drug Use and Health (NSDUH).
Between 2002-2003 and 2016-2017, the adjusted prevalence of past-month cannabis use rose from 3.4% to 7% among pregnant women, and from 5.7% to 12.1% during the first trimester, federal researchers reported in the Journal of the American Medical Association in June. (JAMA. 2019;322:167-169)
In the advisory, Adams decried the practice of retail dispensaries recommending marijuana to pregnant women for morning sickness.
THC can migrate from the mother's bloodstream to the fetal brain, where it may disrupt the endocannabinoid system, he said. Other research has linked marijuana use in pregnancy with adverse outcomes, including lower birth weight.
The American College of Obstetricians and Gynecologists on Thursday said Adams' advisory is consistent with its advice. Last year, the American Academy of Pediatrics also advised all adolescents and young women against marijuana use during pregnancy, Adams said in his advisory.
The risk from marijuana continues after birth, with THC found in breast milk for up to 6 days after a woman's last recorded use of the drug, Adams said. This exposure has been linked to hyperactivity, poor cognitive function, and other long-term consequences.
"Additionally, marijuana smoke contains many of the same harmful components as tobacco smoke," the surgeon general said. "No one should smoke marijuana or tobacco around a baby."
Adams stressed that key development of the human brain continues to a person's mid-20s, making an individual vulnerable to the effects of addictive substances, Adams said.
He noted that frequent marijuana use during adolescence has been associated with changes in the areas of the brain involved in attention, memory, decision making, and motivation. Deficits in attention and memory have been noted in teenagers even after they abstained from marijuana for a month, he said.
"Marijuana's increasingly widespread availability in multiple and highly potent forms, coupled with a false and dangerous perception of safety among youth, merits a nationwide call to action," Adams said.