Weed and seed

June 7, 2006 2:50 PM

If you were a male in your 30's who wanted to father a child, how long before the 'project launch date' would you stop using marijuana?

I smoke marijuana about once or twice a week on average. Some time in the next year or so, I'm going to be expected to impregnate a woman. I've done my Google research, and I've found several articles stating that marijuana decreases fertility. Most are rather vague. This one was the most specific I could find, and the study it references was conducted using men who smoked 14 times a week for 5 or more years.

So in the absence of actual research and data, I'm looking for educated guesses from those who know about such things. (ie, doctors, fertility experts, or people who have a solid understanding of how chemicals affect the body, and for how long.)

Would smoking marijuana once or twice a week be likely to impact a man's fertility? After stopping marijuana use, how long would it take for fertility to return to normal?

posted by anonymous to Health & Fitness (16 answers total)

I would stop about 30 years before it. And this is not because I think that MJ is bad in general. I actually am of the opinion that it should be legal and alcohol illegal if the reasons given by the government in the US were true. However, the evidence of links between THT (is that the right abbreviation) and birth defects are too big to ignore.

Apparently, malformed sperm is one of the reasons that I have seen for the infertility resulting from MJ.
posted by slavlin at 3:36 PM on June 7, 2006

What? THT? Would you care to provide some links to studies on this? Because this would be entirely new to me. There are a lot of people who have smoked marijuana in their life and I think the simple fact is if there were "birth defects too big to ignore" we'd see less amiguous studies about incredibly heavy smokers that "may have infertility problems" and more concrete data. This reminds me of the whole crack baby scare.
posted by geoff. at 3:43 PM on June 7, 2006 [1 favorite]

This is completely anecdotal...
My sister has ovulated twice since college. Both times, she got pregnant by my pot-smoking brother-in-law. I would guess that he smokes almost, if not, every day.
posted by clh at 3:46 PM on June 7, 2006

slavlin: no offense, but asking 'is that the right abbreviation' doesn't boost your credibility. And, since you haven't provided blueprints for a time machine, your advice to anonymous (stop smoking thirty years ago) doesn't seem very helpful.

anonymous: The research summary you link to notes that many marijuana smokers have fathered children. The researcher speculates that, in the case of borderline-infertile men, marijuana smoking may be the thing that pushes them over the edge. Do you know anything about your fertility? If I were you, I'd wait and see if my partner and I seemed to be having trouble conceiving before doing anything further.
posted by box at 3:52 PM on June 7, 2006

According to this, moderate use of the drug will result in several sexual side effects that make make it harder to conceive, but may not lead to any specific type of birth defects. So, you may have to worry about decreased sperm counts and ED depending on your usage patterns. The ED is reason enough to consider stopping, but your usage is not excessive (though I don't condone it b/c is is illegal, but that's beside the point)

Marijuana does take around 2-3 weeks on average to clear from your system because it is fat soluble (you can use google for more in-depth science here). What I would advocate here is the "better safe than sorry" approach. Whether or not there are cited instances of birth defects stemming from use, you'd probably be wise to not smoke for about 4-6 weeks beforehand to make sure all of the THC has left your body. [My 4-6 week estimate is the 2-3 week residual time multiplied by a safety factor of 2 to adjust for any person-to-person differences in adsorption rates and flushing rates].

BTW, the active drug in pot is THC, aka tetrahydrocannabinol, not THT.

From experience, though, many people I know start making positive diet and excercise changes (and drug/alcohol changes) about 3-6 months before conceiving to make sure no effects linger. This might be a safe route for general well-being and health improvements, but is not a scientific number.

When it comes to kids, though, err on the side of caution and at least do the 4-6 weeks (1 month).
posted by galimatias at 3:55 PM on June 7, 2006

I suspect you need a month as a bare minimum, given that's how long it takes the fat-soluble THC to diminish in your system to where it's not reliably testable. How long any fertility repercussions might last past the the point I think you will have a hard time finding any concrete information on.
posted by phearlez at 4:06 PM on June 7, 2006

More confirmation that fertility is affected.

According to this study by Yale, "Marijuana—Many studies have been done on animals with marijuana, but studies are not the same as with humans. No solid evidence has been found to indicate that marijuana smoking may lead to birth defects. Some studies do indicate that THC (the active ingredient in marijuana) may have effects on the genes, and may interfere with the response to infection. We do know that THC can pass into the placenta and to the fetus from animal studies, And nursing mothers would almost certainly pass the THC in her milk. Experts advise pregnant women to avoid marijuana, because its dangers are still unknown. "

So, while there is no concrete evidence marijuana will cause birth defects, there is enough uncertainty to warrant staying cautious.
posted by galimatias at 4:10 PM on June 7, 2006

Sperm is created and lasted a couple of weeks. THC lasts in the system a couple of weeks.

Don't smoke for a couple of weeks before you're planning on doing the deed.

Pretty simple.
posted by wilful at 4:50 PM on June 7, 2006

The life cycle of a sperm (if you could call it that) is about 60 days--from the time the germ cell (spermatogonium) divides to the time the final product is ejaculated.

Make of that what you will...
posted by needs more cowbell at 5:02 PM on June 7, 2006

Building one sperm takes about 70 days from start to finish. Anything that happens during that time can reduce fertility for an extended period of time. For instance, if you run a high fever, you can effectively kill all the sperm in the production channel, and be infertile or less fertile for the next 70 days until new ones are produced from scratch.

So, if marijuana reduces fertility (and smoking tobacco definitely does, so I have no problem believing marijuana does too), you will have to eliminate that from your system, however long that takes, and then wait 70 more days for maximum fertility.

Alos, please note that fertility in males declines with age. Not as sharply as with women, but you are quite a bit less fertile at 30 than at 18. The woman too, is quite a bit less fertile. So all things considered, if you really want to maximize your reproductive odds, you should probably stop smoking today, start taking zinc and anti-oxidant supplements today, and quite possibly start trying to conceive today. Perhaps a lot of birth control education has beat it into people's heads that reproduction is nearly automatic, but once you're in your 30's that is most definitely not true. Start early, and maybe you'll have a pregnancy by the time you wanted to actually start trying.

If you're curious: you can go get a semen analysis done at a local fertility clinic. Cost is not that high, maybe $75-150 depending. You'll know right away whether you currently have super-duper sperm or wimpy-ass sperm, and perhaps that will aid your marijuana decision.
posted by jellicle at 5:13 PM on June 7, 2006

While THC, in vitro (I have a feeling that they're fuding a little on what they call recreational/therapeutic dosages when translating it to how much THC to squirt into test tubes of sperm) can decrease sperm motility.

This review suggests that only in chronic users of chronic does one see statistically significant differences in lowered testosterone (but also notes that others have not been able to reproduce the data).

Apparently marijuana use more significantly impacts the female reproductive system than the male, and the effects appear, generally, to be acute (like, shortly after smoking up) so I'd imagine a week or a month will return you to pre-smoking baselines - especially since you're a light/moderate user. I can mail you the review if you're interested.
posted by porpoise at 8:28 PM on June 7, 2006

I think a good rule of thumb is to avoid most non vital drugs for 1 -2 months prior to conception. Including alcohol.
posted by edgeways at 8:30 PM on June 7, 2006

I 've smoked plenty of marijuana, am 30 years old, and had little to no trouble knocking my wife up. Also, the baby is totally normal. I'm sure that there have been hundreds of thousands of babies concieved by stoners.
posted by trbrts at 8:59 PM on June 7, 2006

Whatever about the weed and birth defects. Genetics can induce defects.

I know plenty of healthy babies born to 1-2 pot smoking parents who are fine. I'd say just get busy with your lady, and if you don't knock her up then quit the ganja and see if that helps.
posted by frecklefaerie at 10:34 AM on June 8, 2006

Stop smoking the weed. Get a haircut. Lose the tie-dyed clothes and sandals. Get a job. Join a gym. Stay clean.

Little Timmy depends on you now.
posted by xpermanentx at 6:32 AM on June 9, 2006

I don't think there is any doubt that healthy children can be born to people who smoke pot. Healthy children can also be born to women who drink alcohol during pregnancy (not that the two have equal risk factors). But, if stopping smoking for a month or two prior to conception would reduce the risk, however slightly, I would think it would be a good trade off. If you can't stop smoking for that length of time that's a different issue.
posted by edgeways at 8:43 AM on June 9, 2006