If a mother quits meth a month before birth will it show in baby?

No: It will not show in the baby's blood or urine. Never ever expose yourself or your child to this again, however. Get into treatment if you have to. If you love your baby and want him or her to have a respectable life, then you will stop. If not, do not be surprised if your child is eventually taken away, a scenario i hope you care enough to avoid. Do the right thing.