Well i can't tell you an good reference sites on the subject. However, my mother smoked pot when she was pregnant with me and my siblings. Also my aunt did the same when she was carrying my cousins. 3 out of 5 of us got degree's, 4 out of 5 play a musical instrument, no brain damage, no criminal tendencies, no short bus, 5 average kids, turned into 5 average adults. I cannot, however tell you the amount or frequency of usage during any of the pregnancies. That being said, even though i, as well as my relatives turned out just fine, (above average in many ways) i would advise against it. Why tempt fate, 9 months is not that long to wait in my opinion, and you will sleep more comfortably without wondering if there will be any consequences for the baby in the future.