Marijuana is more widely available than ever, but what does it do to babies?
There’s no answer to that yet, but nursing mothers are being warned to avoid it: Traces of the drug can show up in breast milk, according to the American Academy of Pediatrics.
Tetrahydrocannabinol, or THC, the psychoactive ingredient in marijuana that gets people high, can be detected in breast milk up to six days after use of the drug, according to a study published on Monday by the journal Pediatrics.
The study found that tetrahydrocannabinol was detectable in 63 percent of 54 samples of breast milk from women who said they had used marijuana before pumping.
In response to evidence that babies are being exposed to marijuana, the A.A.P. recommends that women avoid the drug altogether when they are pregnant or breast-feeding.
Research into the potential effects of marijuana has become particularly relevant as more states have moved toward legalization and expectant mothers have taken up the drug in increasing numbers. Recreational use is legal in eight states and Washington, and 30 states allow for some form of medical use. New York recently took a step toward allowing recreational marijuana.
The move toward legalization has gained momentum in countries like Canada and Britain, while attracting big dollars from investors looking to take advantage of growth in the industry. The parent company of Corona beer recently plunged $4 billion into a cannabis producer.
But the A.A.P. warned that in spite of loosening restrictions, it isn’t necessarily safe for the baby.
“The fact that marijuana is legal in many states may give the impression the drug is harmless during pregnancy, especially with stories swirling on social media about using it for nausea with morning sickness,” said Sheryl A. Ryan, chairwoman of the A.A.P. Committee on Substance Use and Prevention. “But in fact, this is still a big question.”
Preliminary research has suggested that THC can cross the placenta and reach the fetus, potentially harming brain development, cognition and birth weight. But studies on the effects of marijuana on pregnancy and lactation are relatively rare.
The A.A.P. study, which tested breast milk rather than the babies, does not provide evidence of how or if children are affected. It also noted that the amount ingested by infants could vary significantly.
Work on the topic is all the more important now as pot has become more potent, said Christina D. Chambers, a professor of pediatrics at the University of California, San Diego, and one of the authors of the study. “We needed current-day use of currently available products to really understand exposure levels and to look at outcomes that are relevant to today,” she said in an email.
More research is needed so doctors can provide evidence-based advice, Dr. Chambers added. “This creates a dilemma for pediatricians who want their patients to be breast-fed and worry that some mothers, if told not to use cannabis, may not breast-feed.”