# How long does weed stay in the system
**URL:** https://boards.straightdope.com/t/how-long-does-weed-stay-in-the-system/723125
**Category:** Factual Questions
**Created:** [June 22, 2015, 5:11am UTC](https://boards.straightdope.com/t/how-long-does-weed-stay-in-the-system/723125 "2015-06-22T05:11:30Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@Nzinga\_Seated](https://boards.straightdope.com/u/Nzinga_Seated)
#### Post date: [June 22, 2015, 5:11am UTC](https://boards.straightdope.com/t/how-long-does-weed-stay-in-the-system/723125/1 "2015-06-22T05:11:30Z")
I have a friend who claims she didn’t know she was pregnant till she was 5 months. She smoked weed till then, but quit. They will test her baby . Will it come back positive?
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### Author:  [@Disgruntled\_Penguin](https://boards.straightdope.com/u/Disgruntled_Penguin)
#### Post date: [June 22, 2015, 5:28am UTC](https://boards.straightdope.com/t/how-long-does-weed-stay-in-the-system/723125/2 "2015-06-22T05:28:08Z")
> [@Nzinga\_Seated](#):
>
> I have a friend who claims she didn’t know she was pregnant till she was 5 months. She smoked weed till then, but quit. They will test her baby . Will it come back positive?
It stays in your system approximately 2-3 weeks so assuming a 9 months birth the child should test clean.
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### Author:  [@Nzinga\_Seated](https://boards.straightdope.com/u/Nzinga_Seated)
#### Post date: [June 22, 2015, 5:33am UTC](https://boards.straightdope.com/t/how-long-does-weed-stay-in-the-system/723125/3 "2015-06-22T05:33:08Z")
Thanks for hollerin back playa. But here’s the thing. She said her cousin got a visit from CPS and hadn’t smoked for months. The tested the baby’s first BM. She’s so scared.
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### Author:  [@Oakminster](https://boards.straightdope.com/u/Oakminster)
#### Post date: [June 22, 2015, 5:40am UTC](https://boards.straightdope.com/t/how-long-does-weed-stay-in-the-system/723125/4 "2015-06-22T05:40:00Z")
I dunno about babies, but the hair and fingernail tests can detect drug use for months after the fact.
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### Author:  [@bardos](https://boards.straightdope.com/u/bardos)
#### Post date: [June 22, 2015, 6:20am UTC](https://boards.straightdope.com/t/how-long-does-weed-stay-in-the-system/723125/5 "2015-06-22T06:20:18Z")
Who is “they” and why will they drug test a baby?
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### Author:  [@grude](https://boards.straightdope.com/u/grude)
#### Post date: [June 22, 2015, 6:28am UTC](https://boards.straightdope.com/t/how-long-does-weed-stay-in-the-system/723125/6 "2015-06-22T06:28:27Z")
> [@bardos](#):
>
> Who is “they” and why will they drug test a baby?
The question I was going to ask.
Are you guys saying it is standard now in the US for all babies to be drug tested by the hospital I guess? How does this even work, can’t she refuse the drug test as she is guardian?
Is there even any evidence THC is harmful to a fetus?
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### Author:  [@madsircool](https://boards.straightdope.com/u/madsircool)
#### Post date: [June 22, 2015, 6:32am UTC](https://boards.straightdope.com/t/how-long-does-weed-stay-in-the-system/723125/7 "2015-06-22T06:32:01Z")
Marijuana is harmful to young brains:
> **[Regular marijuana use bad for teens' brains](https://www.apa.org/news/press/releases/2014/08/regular-marijuana)**
>
> Frequent marijuana use can have a significant negative effect on the brains of teenagers and young adults, including cognitive decline, poor attention and memory, and decreased IQ, according to psychologists discussing public health implications of...
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### Author:  [@Nzinga\_Seated](https://boards.straightdope.com/u/Nzinga_Seated)
#### Post date: [June 22, 2015, 8:30am UTC](https://boards.straightdope.com/t/how-long-does-weed-stay-in-the-system/723125/8 "2015-06-22T08:30:33Z")
> [@grude](#):
>
> The question I was going to ask.
>
> Are you guys saying it is standard now in the US for all babies to be drug tested by the hospital I guess? How does this even work, can’t she refuse the drug test as she is guardian?
>
> Is there even any evidence THC is harmful to a fetus?
Yeah. She’s in Michigan. They is the hospital.
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### Author:  [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)
#### Post date: [June 22, 2015, 9:14am UTC](https://boards.straightdope.com/t/how-long-does-weed-stay-in-the-system/723125/9 "2015-06-22T09:14:28Z")
Marijuana is one of the most durable drugs in a human body. If you’re a regular user, it can still be detected a month or two after you stop using it. But she should be outside that window from what you’re saying.
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### Author:  [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)
#### Post date: [June 22, 2015, 9:17am UTC](https://boards.straightdope.com/t/how-long-does-weed-stay-in-the-system/723125/10 "2015-06-22T09:17:43Z")
> [@Oakminster](#):
>
> I dunno about babies, but the hair and fingernail tests can detect drug use for months after the fact.
Remember the news stories when Britney Spears shaved her head? What they didn’t say was that she was in a custody battle with her ex-husband and there was the possibility she might be required to submit to a drug test.
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### Author:  [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)
#### Post date: [June 22, 2015, 1:28pm UTC](https://boards.straightdope.com/t/how-long-does-weed-stay-in-the-system/723125/11 "2015-06-22T13:28:52Z")
The only source for that Britney story is Sam Lutfi, who was suing her at the time, so I would take it with a grain of salt.
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### Author:  [@Nava](https://boards.straightdope.com/u/Nava)
#### Post date: [June 22, 2015, 1:45pm UTC](https://boards.straightdope.com/t/how-long-does-weed-stay-in-the-system/723125/12 "2015-06-22T13:45:27Z")
A related question would be whether THC will pass the placental barrier. And the answer appears to be “yes”; cannabinoids are also found in breast milk of pot smokers. Whether that is bad for the baby or not seems to be more of a grey area - which I take to mean “it doesn’t seem to be terribly bad or we’d have people yelling it from roofs”.
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### Author:  [@Nzinga\_Seated](https://boards.straightdope.com/u/Nzinga_Seated)
#### Post date: [June 22, 2015, 2:17pm UTC](https://boards.straightdope.com/t/how-long-does-weed-stay-in-the-system/723125/13 "2015-06-22T14:17:26Z")
Thanks guys.
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### Author:  [@DrCube](https://boards.straightdope.com/u/DrCube)
#### Post date: [June 22, 2015, 2:49pm UTC](https://boards.straightdope.com/t/how-long-does-weed-stay-in-the-system/723125/14 "2015-06-22T14:49:47Z")
> [@Nzinga\_Seated](#):
>
> Yeah. She’s in Michigan. They is the hospital.
She can’t just say no? Is she on probation or parole or something? I can’t see any other reason they could compel her to allow this test on her newborn.
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### Author:  [@CGav8r](https://boards.straightdope.com/u/CGav8r)
#### Post date: [June 22, 2015, 3:11pm UTC](https://boards.straightdope.com/t/how-long-does-weed-stay-in-the-system/723125/15 "2015-06-22T15:11:24Z")
> [@DrCube](#):
>
> She can’t just say no? Is she on probation or parole or something? I can’t see any other reason they could compel her to allow this test on her newborn.
In the hospital’s defense, the baby came out with dreads and a hemp "Phish"onesie on, so they are right to be suspicious.
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### Author:  [@Nzinga\_Seated](https://boards.straightdope.com/u/Nzinga_Seated)
#### Post date: [June 22, 2015, 8:01pm UTC](https://boards.straightdope.com/t/how-long-does-weed-stay-in-the-system/723125/16 "2015-06-22T20:01:17Z")
No she can’t just say no. Michigan law
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### Author:  [@usedtobe](https://boards.straightdope.com/u/usedtobe)
#### Post date: [June 22, 2015, 10:03pm UTC](https://boards.straightdope.com/t/how-long-does-weed-stay-in-the-system/723125/17 "2015-06-22T22:03:21Z")
> [@Nzinga\_Seated](#):
>
> No she can’t just say no. Michigan law
Does anyone else find this as scary as hell?
What next? Seize the kid (AND the placenta) at birth and require the mother to prove herself a fit parent before returning her child?
What is the MI position on refusing vaccines? I do hope they are at least as protective of a toddler as they are of fetuses.
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### Author:  [@DrCube](https://boards.straightdope.com/u/DrCube)
#### Post date: [June 22, 2015, 10:12pm UTC](https://boards.straightdope.com/t/how-long-does-weed-stay-in-the-system/723125/18 "2015-06-22T22:12:55Z")
> [@Nzinga\_Seated](#):
>
> No she can’t just say no. Michigan law
Seriously? That’s bullshit. I’d just get up and leave the hospital. Are there bars on the windows and doors?
(I’m not blaming your friend. I’m just shocked and pissed to find out that hospitals in a state I used to live in are actually prisons now?)
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### Author:  [@Clark\_Cello](https://boards.straightdope.com/u/Clark_Cello)
#### Post date: [June 22, 2015, 10:20pm UTC](https://boards.straightdope.com/t/how-long-does-weed-stay-in-the-system/723125/19 "2015-06-22T22:20:12Z")
> [@Nzinga\_Seated](#):
>
> No she can’t just say no. Michigan law
Do you have a cite on this? Not that I don’t believe you, just never heard of it, and it does seem excessive.
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### Author:  [@grude](https://boards.straightdope.com/u/grude)
#### Post date: [June 22, 2015, 10:34pm UTC](https://boards.straightdope.com/t/how-long-does-weed-stay-in-the-system/723125/20 "2015-06-22T22:34:07Z")
> [@usedtobe](#):
>
> Does anyone else find this as scary as hell?
>
> What next? Seize the kid (AND the placenta) at birth and require the mother to prove herself a fit parent before returning her child?
>
> What is the MI position on refusing vaccines? I do hope they are at least as protective of a toddler as they are of fetuses.
I do, I mean WTF forced medical procedure?
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