Opinions?

Jessie
Ive heard many people say it, and even doctors told me. But I'd like to know what your opinions are about cannabis use during pregnancy.
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I'm 7 weeks and my OB told me that it's safe to use and I do for nausea and the back pains. Now, I still worry about actual smoke being in my system, but I barely have to smoke much and it's more effective for me than any anti-nausea medication. 
​What do you guys think about it?