What You Need to Know About Smoking Pot While Breastfeeding, According to New Study

When a breastfeeding mom mentions she's "pumping and dumping," it more often than not means she's had a drink or two and doesn't want to feed her baby milk that could contain alcohol. However, studies have found that little alcohol appears in breast milk after mom has a few cold ones. Now, a new study published in the Journal of Obstetrics and Gynecology is exploring the levels of delta-9-tetrahydrocannabinol (THC) that might be in a mom's breast milk as a result of a nursing mom smoking pot — and the findings aren't all that different when compared to those studies looking at blood alcohol content.

The study looked at eight new mothers who were all at least occasional pot smokers with exclusively breastfed babies ages 2 to 5 months. Breast milk samples were collected from each mom after discontinuing pot smoking for 24 hours, then again 20 minutes, one hour, two hours, and four hours after smoking a "preweighed, analyzed, standardized strain of cannabis from one preselected dispensary" — 0.1 grams of cannabis, containing a 23.18 percent concentration of THC.

The amounts of THC that transferred into the mothers' milk samples were "detected at low concentrations" each time a collection was made after the moms smoked, but was highest an hour after smoking. It was estimated that 2.5 percent of the maternal dose of THC was ingested by the babies.

"The levels are low in the milk, and even less would be absorbed by the infants," study author Tom Hale, PhD, professor of pediatrics at the Texas Tech University School of Medicine, executive director of the school's InfantRisk Center, told Healthline.

Although the levels of THC passed through the breast milk and to the babies would be low, the study notes that "mothers should be cautious using cannabis during pregnancy and breastfeeding," as the long-term effects of THC on the developing brain are unclear.