In a study seemingly designed to confirm the obvious, researchers in Sweden and Austria have determined that no, you shouldn’t smoke weed while pregnant. It seems that THC, the psychoactive ingredient in marijuana, may inhibit the formation of normal connections between nerve cells and the cerebral cortex in the prenatal brain, which could result in psychiatric and cognitive disorders. The researchers aren’t sure exactly how it works, but they’re nonetheless advising pregnant mothers not to smoke, eat, or otherwise ingest marijuana. And yes, that includes medical marijuana.
Tibor Harkany and his team attempted to measure the effect of marijuana on prenatal brains in a couple ways ways, including injecting pregnant mice with THC and studying the brains of aborted fetuses whose mothers claimed to have used marijuana during pregnancy. In the brains of both human and mouse fetuses, there was a lower level of Superior Cervical Ganglion 10 (SCG10), a protein that plays a crucial role in brain wiring in developing brains. The end result of this deficiency is unclear; it could directly result in cognitive or psychiatric disorders, or simply make the brain more susceptible to drug exposure or neuropsychiatric illnesses later in life.
The bottom line, though, is that future mothers should “avoid marijuana” after they conceive. Smoking a bit of weed before conception, on the other hand, is apparently fair game, and more likely to affect whether or not a woman actually gets pregnant than the development of the fetus itself.