I am in the first trimester of pregnancy. Although I do not smoke cigarettes, I have smoked pot, heavily before I found out I was pregnant and a few times after. I have stopped now, but I am concerned about the repercussions of my behavior on my unborn child. Can you give me any information?

-L.

There is not a lot of medical evidence on the effects of marijuana -- and marijuana alone -- on pregnancy. Pot users often use other drugs, including alcohol, and it can be difficult to separate out the effects of pot from those of other substances. One study has shown a lower birth weight in babies whose moms smoked pot throughout pregnancy, but other studies have not shown this association.

The bottom line with pot: It contains a tremendous number of substances, many of which have not been identified, and we just do not know the potential long-term consequences if used during pregnancy. Pot, like all other street drugs, should be avoided in pregnancy -- for many of the same reasons that no medication, prescription or otherwise, should be used in pregnancy without your doctor's okay.