Effects of prenatal exposure to marijuana

I am treating a 27-year-old woman who is now in her 10th week of pregnancy. She smokes marijuana two to three times a week, but does not use other drugs. She also smokes 20 cigarettes a day. I am concerned about the effects of marijuana exposure on her baby.

It is not always possible to isolate the effect of marijuana exposure from other possible confounders on pregnancy outcome. Although marijuana is not an established human teratogen, recent well conducted studies suggest it might have subtle negative effects on neurobehavioural outcomes, including sleep disturbances, impaired visual problem solving, hyperactivity, impassivity, inattention, and increased delinquency.