Smoking marijuana during pregnancy?

Christina • 20. Atlanta.05/23/14❤❤❤ soon to be married💑
So my sister and I just dicussed this topic, and we are curious of other peoples thoughts. So has anyone smoked during pregnancy? My sister in law smoked pot her entire pregnancy, and smoked cigarettes! I was very confused as to why she continued her habits, worried for my unborn neice. Anyway, the baby came out healthy and happy, and so calm..the ideal newborn baby. Are there risks when smoking pot during pregnancy? What are your thoughts? :) the reason I am asking cause I have known several people who have smoked while pregnant and they said it helped them with morning sickness and eating but it's still odd to me. Personally, I would feel so guilty if I were to do that. Is it a huge risk factor or harmless?