There is no clear cut answer to your question. We do know that drugs and alcohol can affect a growing fetus but we do not have clear answers about when damage can occur or how much drugs or alcohol it would take to cause harm. One of the reasons that street drugs like ecstacy can be so harmful is that are cut with other drugs and substances like heroin, cocaine, pcp, rat poison and drain cleaner and sometimes these substances can make the drug more harmful or be just as harmful as the drug itself. The best advice I can give in this situation is that any pregnant woman who has used any type of drugs or alcohol during her pregnancy whether she was aware of it or not should speak to her ob or midwife about it, they are there to help.