I smoked marijuana last week and i'm breastfeeding, my baby had blood drawn today to check for illness will it show up in the test ?

Marijuana & nursing: Only if the baby's blood is tested for drugs will it test positive, but you are still exposing your child to dangerous drugs during a time when his or her brain is still developing which could have life long effects.

Possibly: Although published data are limited, it appears that active components of marijuana are excreted into breastmilk in small quantities. Data are from random breastmilk screening rather than controlled studies because of ethical considerations in administering marijuana to nursing mothers.