A Portland mother claims she was barred from breastfeeding her premature baby by her doctor because of her medical marijuana use.

“They’re refusing to allow me to breastfeed,” Crystal Cain told local news station KATU in reference to Oregon Health Science University officials. But the hospital soon changed their ban to a waiver that Cain would sign acknowledging the risks of marijuana use while breastfeeding.

"We can't stop her from using it," says the chief medical officer at Oregon Health Science University.

Cain doesn't believe that smoking pot while breastfeeding is an issue. “There are several studies that indicate that it can’t transfer through your milk ducts. Your body automatically kind of filters it," she said. Cain further explained that she is using marijuana on the advice of her midwife, who recommended it for relieving anxiety and nausea. 

It is not entirely clear if Cain is right or wrong about marijuana and breastfeeding, since there haven't been enough studies despite her claims.

“Although published data are limited, it appears that active components of marijuana are excreted into breastmilk in small quantities,” reads LactMed, the US National Library of Medicine's database on drugs' effects on breastmilk. “Data are from random breastmilk screening rather than controlled studies because of ethical considerations in administering marijuana to nursing mothers.” 

Michael Backes, marijuana expert at the American Academy of Pediatrics, said that cannabinoids are indeed passed through breastmilk, but what kind of effects they have are still unknown.

But it could just be a matter of time before mothers can know for sure. As marijuana becomes legal, demand for studies on its effects will increase to aid better regulations.