Marijuana Use During Pregnancy Affects Baby's Brain

Previous studies have found that exposure to marijuana during pregnancy can increase a child's risk of having cognitive deficits or psychiatric disorders.
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[I[t seems the brain may be particularly sensitive to THC (delta-9-tetrahydrocannabinol) during early development, when neurons are forming critical connections. Any drug that interferes with this development could be detrimental to the child...
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In the study, Harkany and his colleagues tested marijuana's effects in three ways: They grew brain cells from mice in the presence of THC, they injected pregnant mice with THC, and they studied the brains of electively aborted human fetuses whose mothers had used marijuana during pregnancy.
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"Prenatal cannabis disrupts synapses [nerve connections] critical for higher order executive and cognitive function," study researcher Yasmin Hurd, a neuroscientist at Mount Sinai Hospital in New York, told LiveScience in an email.

There is a reason they call it dope.