Dr. Cindy M.P. Duke, M.D., Ph.D., FACOG
This post is in no way meant to be a commentary on Marijuana usage as a lifestyle choice or how one chooses to spend their recreational time. However, if faced with infertility, I would love for my patients and all people considering pregnancy to pay attention to the impact that smoking marijuana (and smoking in general) can have on one’s chances to conceive. I must further preface this post by saying that what I am speaking about is in reference to the hard science, the facts, the data, the research that’s been done for well over 30 years now, looking at the impact of smoking marijuana or ingesting marijuana-containing products, specifically looking at that active ingredient in marijuana, THC, cannabis. I emphasize this, because depending on where you search in the world of the Internet, you would see evidence of articles that are contradictory to what I’m about to say.
The Effects of Smoking in General
Smoking is a long, well-known factor in decreasing one’s fertility. So before we speak about marijuana, I just wanted to spend a few moments to talk about the effect of smoking cigarettes and how it impacts fertility.
The most important takeaway that I want everyone to remember from this session is that smoking affects fertility in both men and women.
So we’re not just talking about smoking and how it affects a woman in terms of her eggs or her fertility potential. We’re also talking about what happens with the male partner in a couple.
In up to 13% of patients coping with infertility smoking has been implicated as the cause of infertility . That’s smoking cigarettes–with nicotine being the major ingredient that’s implicated in decreasing fertility–but we also know that even in people who smoke filtered, tarless, and other types of cigarettes, it’s not just the nicotine content that affects fertility, but all the components of smoking.
Smoking can decrease one’s fertility by up to 30%. To be clear, I’m not saying that smoking causes 30% of infertility. Rather, in any individual person, smoking can decrease one’s ability to get pregnant or cause a pregnancy by up to 30%.
Of course, once one is pregnant, smoking can have a variety of effects and impacts on the pregnancy, with well-documented evidence showing that smoking can impact the continuation of the pregnancy. It can impact how well the baby grows when it’s developing because it impacts the placenta, which is really the nutrition and life source of pregnancy. Everything that the pregnancy needs to help it grow is derived via the placenta and how it interfaces with the mom’s uterus and her blood supply.
More importantly, in terms of looking at how much you smoke, for some people the argument might be, “I smoke, but not a whole lot.” There have been studies that looked at the number of cigarettes smoked and show that even smoking as few as four to five cigarettes per day still impacts one’s fertility and can impact it quite negatively.
Marijuana and Infertility
Based on marijuana studies in both men and women what we know for a fact is that it can actually decrease fertility. In men, we have found cannabis in seminal fluid. We now know that sperm, which are exposed to marijuana in the short term, become hyperactive.
So what does hyperactivity mean? It means that the sperm speed up. And at first when you hear that, you would say, “Dr. Duke, isn’t that the goal? You want the sperm to move.” The answer is yes. However, in terms of the dynamics and physiology of how sperm move, when they move they actually are supposed to move at a certain velocity. And then just before they get to the egg, which is almost like acceleration for that collision with the egg, they should become hyperactive and speed up to collide with the egg.
Unfortunately with marijuana, the sperm speed up from the moment they enter the genital tract and get tired out. They wear out midway on their path to an egg. By the time they arrive, their energy is gone; their movement is gone. They aren’t able to get to the egg and fertilize it.
…that hyperactivity is NOT good.
At first, if you read you’ll see some people fixating on the fact that sperm become hyperactive from marijuana. But that hyperactivity is not good. The truth is that in terms of sperm-egg interaction, that hyperactivity should occur only just before it reaches the egg, not from the start in the tract.
Now, we also know that even if a man doesn’t smoke marijuana but he is with a woman who does, the sperm is still affected within the genital tract of the woman. If sperm is deposited into the vagina, and then it makes its way up into the uterus, into the oviducts or fallopian tubes, and the woman had smoked marijuana, that marijuana is present in her fallopian tubes. The cannabinoid chemical is there. It’s present in the uterine cavity. It’s present in the vagina. And that in turn, again, affects the sperm.
Likewise, for women, eggs can be affected just like sperm, by the presence of THC in either seminal fluid, the vagina, or the fallopian tubes. When a woman ovulates, her egg is captured by the fallopian tube. If a woman is smoking marijuana and she’s released an egg into that environment, she’s exposing the egg to something that is actually known to be toxic for it.
To recap, we know from actual studies and data looking at fertility in men and women that THC can significantly diminish fertility as much as nicotine in cigarettes. So again, if you’re someone suffering from infertility and you use cannabinoid-containing products, I encourage you to highly reconsider either cutting back or ideally discontinuing for the duration of your treatment. What you do after that, again, is a lifestyle choice and up to you.
Q & A
The short answer is, if one continues to smoke or ingest products that contain THC during pregnancy, it can have pretty significant and deleterious effects.
These can range from miscarriage to possible birth defects, if you’re using it in the very early stage of pregnancy. I’m talking about the first trimester, particularly the earlier parts of first trimester. The other question to keep in mind is the source. For some people, when they use marijuana-containing products, they’ve actually been mixing it with other products, other known or not-yet-known substances, at least to the user, that can affect, deleteriously, the forming of a young fetus.
Again, I highly recommend discontinuing use during pregnancy. If you can’t discontinue on your own, there are services available to you to help you quit or cut back and support you through it in a nonjudgmental way.
There’s not any clear data that says smoking can cause cysts or fibroids. However, there are data, a number of data, that support a connection between smoking and the development of certain cancers.
Women who smoke cigarettes are at higher risk of developing cervical cancer and ovarian cancer. Smoking is also associated with uterine cancer. Certainly, smoking has been linked to many forms of cancer but in the realm of gynecologic cancers, smoking has been shown to play a big role. Smoking is directly linked with some of them and some forms of gynecological cancer may be more related to lifestyle choices that are associated with smoking. It varies.
How long does it take to remove the THC or nicotine from your system?
A lot of the data that looked at the effect of THC and nicotine in the context of fertility looked at short-term exposure–what happens if you’ve smoked within the last couple days up to within the last three weeks. We know that THC remains in your system for up to six weeks. Sometimes up to 12 weeks. This is the whole premise behind when someone is tested, for example in the urine, for evidence of exposure to or use of marijuana. It can represent use as recently as the same day, or as far back as up to 12 weeks prior.
Edibles contain cannabis, and what we’re talking about is the impact of cannabis as an active ingredient. So it’s not simply the act of smoking, but also what you’re ingesting. If you are consuming or ingesting marijuana in anyway, it can all also contribute to infertility.