Smoking marijuana while pregnant may raise risks for baby

Sept. 25, 2018, file photo, a police officer shows buds of marijuana before a news conference Bangkok, Thailand. AP Photo/Sakchai Lalit, File
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Marijuana may be more widely available and accepted than ever, but pregnant women may want to think twice. A new report adds to the growing body of evidence that using marijuana during pregnancy could be harmful to children's health.

The study, published in the journal JAMA Psychiatry, finds that women who use pot while pregnant could be putting their child at a slightly increased risk of psychosis. Researchers say it's yet one more reason to be concerned about the significant increase in women using marijuana during pregnancy in recent years.

According to the Centers for Disease Control and Prevention, 1 in 20 women in the U.S. uses cannabis during pregnancy. A study published earlier this year found that's a 75 percent increase from 2002.

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Experts are concerned that as more states legalize marijuana, it may give the false impression that it is safe to use during pregnancy.

"Given increasing cannabis accessibility and potency, as well as growing public perceptions that it's safe to use, it is critical for additional research to understand the potential adverse consequences and benefits of cannabis throughout development and how these associations may arise," senior study author Ryan Bogdan, associate professor of psychological & brain sciences at Washington University in St. Louis, told CBS News.

Bogdan points to a troubling report from 2018 that found many marijuana dispensaries in Colorado, where pot is legal, recommend cannabis as a natural remedy for morning sickness. The findings of that study surprised its lead author Torri Metz, M.D., a perinatologist at Denver Health.

"We did not anticipate that 69 percent of the dispensaries contacted would have a recommendation," she told CBS Denver at the time. "We expected a much higher proportion of them to say that they could not make a recommendation or to encourage women to talk with their health care providers."

While more research is needed to better understand the effects of cannabis on a developing fetus, the American Academy of Pediatrics recommends that pregnant women not use marijuana.

"We do know that THC" — the psychoactive component in marijuana — "crosses into the placenta, and so if a woman is using marijuana during pregnancy it does cross to the fetus, so it's definitely plausible that there would be effects on the fetus," Metz said.

There are concerns about the impact that could have on fetal development, including premature birth and low birth weight. Some research suggests marijuana use during pregnancy may lead to long-term health effects including cognition issues in children later in life, such as their ability to pay attention or learn.

The latest study suggests using marijuana during pregnancy is associated with a small increase in psychosis risk in children between the ages of 8.9 and 11 years old.

Bogdan notes that the study is observational and cannot prove cause and effect and that a number of factors could be contributing to that finding.

"However, this association remained after accounting for a host of potentially confounding factors — for example, maternal education, age at pregnancy, birthweight, prenatal vitamin use, alcohol and nicotine use during pregnancy — which increases the plausibility that prenatal cannabis exposure may contribute to a small risk of increases psychosis proneness among children," he said.

"Until more research accumulates, these data suggest that marijuana use during pregnancy should be discouraged."