Brief Answer:
several possibilities can be there..

Detailed Answer:
Hello Dear, Welcome To HCM..

First of all sorry for the delay in my response..

I've gone through your query and understand your concern..

Now, opiates and meth's clearance is mainly dependent on -

1. Intake and frequency by the mother in the first place..

2. Total duration of intake and the time when last time taken ..

3. Which trimester/ month of pregnancy ?

4. Along with this, few more important parameters like mother's age, body metabolism, overall health, avg. body mass, activity level, avg volume of meconium all play vital roles in this..so you can pretty much understand that based on these many variables, it's almost impossible to predict the exact time line how long opiates/meth can stay in a unborn fetus..

However you should note that Methamphetamine, like many other drugs, can be detected with a hair follicle drug test for up to 90 days.

Hope this'll clear your doubt, feel free to ask if you're having any further doubts, I'll be glad to clarify..

Take Care
Kind Regards

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