In August 2018, the University of California San Diego School of Medicine published results from a study aiming to better understand how much marijuana gets into breast milk of nursing mothers and how long it remains. 

Recent trends have shown that more pregnant women and nursing mothers are using cannabis to help with nausea, pain and sleep. Due to federal regulations that classify marijuana as a Schedule 1 drug, little research has been done to inform women whether cannabis consumption can have ill effects on a baby. Without definitive research on the effects, nursing mothers are warned against consumption and often discontinue nursing, which the World Health Organization recommends exclusively for the first six months of a child’s life. 

Researchers hope that with more research, it can be determined whether there is a safe level of consumption so mothers can continue to breastfeed and use cannabis. 

“Pediatricians are often put into a challenging situation when a breastfeeding mother asks about the safety of marijuana use. We don’t have strong, published data to support advising against use of marijuana while breastfeeding, and if women feel they have to choose, we run the risk of them deciding to stop breastfeeding — something we know is beneficial for both mom and baby,” said Christina Chambers, PhD, MPH, principal investigator of the study, professor in the Department of Pediatrics at UC San Diego School of Medicine, and director of clinical research at Rady Children’s Hospital-San Diego.

The study, performed between 2014 and 2017, used 54 samples of breast milk from 50 breastfeeding women in the Mommy’s Milk Human Milk Research Biorepository at the University of California San Diego.  

The study found that delta-9-tetrahydrocannabinol (delta-9-THC) was measurable in a majority of breast milk samples up to about six days after maternal marijuana use.

While small and preliminary, the study is at least pushing the research forward in hopes that mothers can find a happy medium.