The United States surgeon general on Thursday issued a public warning that smoking or vaping marijuana is dangerous for pregnant women and their developing babies.
At a news conference with other top Trump administration health officials, the surgeon general, Dr. Jerome Adams, said he was concerned that pregnant women, teenagers and others were unaware of the health hazards posed by new, professionally grown marijuana crops.
Retail outlets have recommended marijuana use for morning sickness, the surgeon general’s advisory noted. And doctors are concerned that T.H.C., the high-inducing chemical in marijuana, poses risks for the developing fetal brain, and that it could be passed to infants through breast milk.
Dr. Adams described modern marijuana as far more potent than marijuana produced and sold 20 years ago, with levels of T.H.C. increasing to a range of 12 percent to 25 percent from 4 percent back then.
Thirty-three states have legalized marijuana in some way, either for medical or recreational use. Dr. Adams said that this rapid normalization of marijuana has caused a false sense of safety about its use.
“The scary truth is that the actual potential for harm has increased,” he said. “This ain’t your mother’s marijuana.”
Alex M. Azar II, the secretary of health and human services, standing beside the surgeon general, said that although some state laws have changed, the federal law has not, nor has the science.
“This is a dangerous drug,” Mr. Azar said. “No amount of marijuana use during pregnancy or adolescence is safe.”
The new advisory said that marijuana, or cannabis, is the most commonly used illicit drug in the United States. It said that the potentially harmful effects of marijuana include memory and motor impairments. The newer, more potent strains, he continued, pose other risks, including anxiety, agitation, paranoia and psychosis.
A Kaiser Permanente study, published in July in the journal JAMA Network Open, reported that the number of women using cannabis in the year before they became pregnant, and early in their pregnancy, is increasing. Their examination of self-reported cannabis use among nearly 277,000 pregnant women found that the number who reported daily cannabis use during pregnancy increased to 21 percent from 15 percent.
Mr. Azar said that President Trump had donated $100,000 to pay for a digital campaign to make the public aware of the hazards of vaping, smoking or otherwise using marijuana.
Dr. Elinore F. McCance-Katz, assistant secretary for mental health and substance use, said she was concerned about the possible correlation between marijuana use and increased rates of major depression in adolescents.
“While we cannot say that marijuana is causal of those things, when you look at the increased trend, it is quite concerning,” she said.
Dr. Lauren M. Jansson, pediatric director of the Center for Addiction and Pregnancy at Johns Hopkins Bayview Medical Center in Baltimore, said she was pleased by the surgeon general’s warning, in light of the harmful effects of T.H.C. on developing fetuses and on babies who are being breastfed.
“He’s 100 percent correct,” she said. “No amount of marijuana is safe for pregnant or lactating women. Disturbingly, more and more women are using it.”
