Can smoking marijuana before pregnancy cause any complications while pregnancy?

It certainly might. It appears that exposure to marijuana during embryonic/fetal development can cause behavior problems. Exactly when during development the danger happens is unknown but we do know that marijuana substances can stay in your body for quite some time even after you stop. Why subject your children to such risk? Besides all this, smoking *anything* puts carbon monoxide and other poisons in your body.
Smoking marihuana. Marihuana can cause symptoms similar to schizophrenia and advise u to take it.