50 years ago, scientists warned of marijuana’s effects on the unborn

Excerpt from the September 27, 1969 issue of Science News

a photo of a person smoking marijuana

POT PLUS PREGNANCY  Scientists are still figuring out how marijuana use by pregnant women might affect developing fetuses.

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cover of September 27, 1969, issue of Science News

Pinning down the weed, Science News, September 27, 1969 —

New research hints that marijuana may have serious physiological effects that should make it, like cigarettes, carry a warning … The possibility that marijuana is teratogenic, causing damage to unborn children, is a specter that as yet cannot be put down … [T]here is already some information indicating that THC readily crosses the placenta and enters the fetus.


Marijuana use by pregnant women is on the rise, with some using it to treat morning sickness (SN Online: 09/11/18). In a U.S. national survey that included more than 4,000 pregnant women, marijuana use roughly doubled between 2002 and 2017 from 3.4 percent to 7 percent, researchers reported June 18 in JAMA. And in a different study in the same issue, self-reported marijuana use by pregnant women was linked to a greater risk of premature birth. A recent study in rats, presented at Experimental Biology 2019 in Orlando, Fla., found that cannabis may change the nerve connections in the brain’s hippocampus, which plays a role in learning and memory.

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