Brief Answer:
Risk of detection is rare.

Detailed Answer:
Hello thanks for asking from HCM for your health related queries

I can understand your concern. If a woman quit about 3 weeks prior to giving birth to a baby then chances that the baby hair follicles will test positive are very very less. The baby is five weeks old so total 8 weeks has passed, so the risk is really very low. This depends upon growth factors and hair growth of baby which is different in different babies. But as the woman if quitting 3 weeks prior to delivering the baby and baby is 5 weeks old so the risk of detection is very very low, no need to worry.

Thanks, Take care

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