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WSU researchers explore link between ingesting marijuana and breast milk

Courtesy U.S. Department of Agriculture

Washington State University researchers have found mothers who smoke marijuana pass along some of its psychotropic compounds through their breast milk.

Courtney Meehan studies human milk. She’s the associate dean for research and graduate studies for WSU’s College of Arts and Sciences and a professor of anthropology. She and her research team collected samples from 20 mothers in Washington and Oregon who reported smoking marijuana at least once a week.

“We asked them to abstain from cannabis use for 12 hours and then, following that, on their own time and following an initial use of cannabis, they collected an additional five milk samples for us,” she said.

Meehan says the team analyzed the samples and found little consistency from mother to mother.

“For participants in our study who used cannabis only one time during the study, THC peaked approximately 30 minutes to 2 1/2 hours after use and then it started to decline,” she said.

For the women who use more often, Meehan says the compounds often stay in the mothers’ bodies for longer.

How the exposure to THC affects the child isn’t yet clear. Meehan says little research has been done in this field, in part because she says women have often not been included in medical clinical trials. There have also been restrictions related to doing work on people ingesting an illegal substance. But now that recreational marijuana is legal in Washington, she believes scientists will do more scholarship in this area.

Meehan was also part of a second study that explored why mothers who breastfeed are using cannabis.

“We found that they are using for a variety of therapeutic purposes, to relieve anxiety, to assist with other mental health issues or chronic pain. They report choosing cannabis over using other medications because they felt that it was safer,” she said.

Their study reports 80% of the participants “reported very few or no concerns about using cannabis while breastfeeding, although participants who used cannabis for medical purposes had significantly more concerns.” They also reported receiving little or no advice on cannabis use from their health care providers.

Meehan says she and her team expect to continue their research in this area.

One of the Northwest's most seasoned reporters is returning to his SPR roots. Doug Nadvornick will be heard frequently on KPBX and KSFC reporting on local news.