Hi there, thanks for asking. As you mentioned these drugs should not be used during
pregnancy.
Methamphetamine could cause
low birth weight for the child. Alcohol also cause low birth weight and fetal alcoholic syndrome especially if it used regularly.
Xanax could cause cleft lip/
palate in 2 percent of the cases. I think it is absolutely better you talk with your doctor about this issue. There are good methods to manage dependence during pregnancy which includes mostly non pharmacological approaches. They may use of some medications which have the minimum risk for the baby as well. I wish the best health for you and your baby.