UW ‘Moms and Marijuana' study faces new questions amid surgeon general warning

SEATTLE — As the surgeon general issues a public warning that marijuana is dangerous for pregnant women, University of Washington Medicine is pushing forward with a controversial study.

>> UW study looks at how marijuana impacts infants’ brain development

The research — aptly titled “Moms + Marijuana” — aims to examine marijuana use exclusively among pregnant women who don’t use other substances and/or alcohol.

“The very few investigations that have studied prenatal cannabis exposure and infant brain development have all involved women who are poly-substance drug abusers,” said Dr. Natalia Kleinhans, the study’s lead researcher.

Mainstream medicine already advises pregnant women against using cannabis to relieve morning sickness, citing studies suggesting it might negatively affect fetal growth, including low birth weight and infant brain deficits.

Supporters of the UW study said while they agree marijuana consumption during pregnancy is ill-advised, there’s also the need for more evidence.

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“I don’t think the surgeon general’s advisory says that we know everything and therefore we don’t need anymore research,” said Dr. Susan Weiss, who directs outside research for the National Institute on Drug Abuse. NIDA provided nearly $200,000 for the UW study.

Dr. Kleinhans said she hopes to recruit 70 pregnant women during their first trimester. Half will already use marijuana at least twice a week. The other half will be clean. Their infants will undergo brain scans at six months to compare their development. While the participating women are paid $300, researchers will not provide the pot.

“I would absolutely not conduct a study where researchers were administering marijuana to pregnant women or randomizing women to be taking marijuana,” said Dr. Weiss. “That would be an incredibly unethical thing to do at this point in time.”

The research comes as surveys show the number of women using cannabis in the year before they became pregnant or early on in their pregnancy increases. U.S. Surgeon General Jerome Adams said marijuana is the most commonly used illicit drug among pregnant women. A 2017 study showed about seven percent reported using it within the past month.

"Not enough people know that today's marijuana is far more potent than in days past," said Adams on Thursday as he issued the public warning. "This ain't your mother's marijuana."

Adams said he’s concerned pregnant women are unaware of the hazards as marijuana becomes more mainstream and more potent. He said the products produced today include pot’s main active ingredient, THC, with levels of at least 12 percent, a three-fold increase over the last 20 years.

>> Babies of cannabis-using rats show negative cognitive effects

Health and Human Services Secretary Alex Azar stood alongside Adams on Thursday stating that “no amount of marijuana use during pregnancy” is safe.

“When a pregnant woman uses marijuana, THC can enter the baby’s brain and poses risks for its development, a risk that continues during breastfeeding,” said Azar.

Critics of the UW study have called it bogus, arguing it unnecessarily threatens fetuses. But, NIDA has said the changing marijuana culture is one reason the UW study is so vital because previous research has not considered the latest products on the market.

“A lot of the data we have is from the previous generation of people who are primarily smoking marijuana,” said Dr. Susan Collins, co-director of the Harm Reduction Research and Treatment Center in Seattle. “That’s not going to necessarily be very indicative of what happens when people are vaping cannabis or people are using edibles or people are drinking teas or consuming it in the various different ways that are on the market these days.”

The “Moms and Marijuana” study requires participants to purchase marijuana only from licensed sellers, and send photos of the products they’re using so researchers can track the amount of THC and cannabidiol, a non-active compound in marijuana.

“We shouldn’t not do research on people who are using substances because we wish that they weren’t doing substances,” said Collins. “But it is a good idea to be watching substance users and seeing how their behavior is affecting themselves, their communities, their families.”