Marijuana’s impact on fertility is a topic of hot debate. The good news is that cannabis won’t cause any lasting damage in regards to your ability to conceive. But, the bad news? If you’re having trouble getting pregnant, marijuana might not make conception any easier. Here’s the scoop on how marijuana impacts human fertility:
First off, it’s entirely possible to conceive a child after smoking marijuana. However, most available research recognizes that marijuana can put a damper on your spunk. Here’s an overview on just how marijuana might impact your fertility:
There’s a lot of controversy over marijuana’s impact on testosterone levels. When it’s time to start a family, testosterone is something to be aware of. The hormone plays a major role in sperm development. Having “low T” can mean a lower sperm count, which makes it more difficult to conceive a child.
An early piece published in 1981 by the New York Times discussed research that found marijuana impacts male sex drive in two distinct phases. First, marijuana increases testosterone and other sex hormones. Second, it causes sudden testosterone drops. During the second phase, researchers found that sex hormones dropped to well below normal levels.
Using animal models, Susan Dalterio of the University of Texas Health Center in San Antonio found that high doses of THC caused testosterone to spike to 6 times typical levels for the first 20 minutes after smoking. In small doses, the testosterone spike lasted about an hour before levels began to drop.
The drop in testosterone levels found in Dalterio’s study is corroborated by research from 1974 and a research review from 1984. These early reports found that THC and possibly other cannabinoids impact the production of a couple of specific hormones. The hormones in question are luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Both of these are critical to the development of testosterone.
Yet, things are more complicated than they seem. One published last year in the American Journal of Epidemiology found that marijuana use was actually associated with higher testosterone levels, but lower total sperm counts. This study examined 1,215 Danish men between the ages of 18 to 28. A whopping 45% of these young men used marijuana. While testosterone levels in marijuana smokers showed a similar increase to that of cigarette smokers, the participants’ viable sperm count dropped an average of about 29% compared to non-users.
As testosterone is a key hormone in sperm production, the sudden spikes and dips seen among marijuana smokers may be partly to blame for low counts. Though, much more clinical research is needed to understand just how cannabinoids impact basic reproductive functions.
There may be some bad news for marijuana-loving men under 30. According to a study published in Human Reproduction in 2014, smoking marijuana regularly changes the size and shape of your sperm. Researchers from the University of Sheffield found that the chances of producing abnormally shaped sperm increases in young men that use marijuana. The abundance of abnormal sperm cells can make it challenging to reproduce.
The study is one of the largest to date exploring lifestyle impacts on fertility. 2,249 men from 14 fertility clinics around the United Kingdom were sent home with a detailed lifestyle questionnaire. Of the participants, 318 men had samples containing less than 4% normal, healthy sperm.
When researchers compared questionnaire results with samples containing mostly abnormal sperm, they found a couple of interesting things. First, samples from men who ejaculated during the summer were twice as likely to have low counts of normal sperm. If the man in question was under 30, then it was likely that he had used cannabis within three months prior to getting his little soldiers tested.
Lead author Dr. Allan Pacey told The Independent:
We found that cannabis doubled the risk of men under 30 having poor sperm – statistically it jumped out of the analysis. I think it’s a real effect, and it’s not been shown before in such a robust way.
The good news is that new sperm is regenerated in 74-day cycles. If you’re looking to start a family and you haven’t had success, laying off the herb until your body generates a new round of troops might get things back to normal. Having your sperm tested at a fertility clinic can also tell you just how healthy it actually is. Even if you smoke marijuana, you may still have enough healthy sperm to conceive.
Female fertility is a ridiculously complex phenomenon. Not only does it comprise of the ability to become pregnant, but it includes the scientific miracle of growing another human being inside of you. The biochemical processes that enable life to grow and thrive inside the womb are incredible, and there are many different points where cannabis may influence what happens.
Long-term consequences of marijuana on ovulation have yet to be established. Ovulation, or when an egg is released, is triggered because of a timely surge of a particular sex hormone. That hormone is luteinizing hormone (LH). A 2002 review of clinical literature published in the Journal of Pharmacology found that marijuana decreases the level of LH secreted by the pituitary gland. This shouldn’t be surprising since LH is also decreased in men.
One of the studies cited in the literature review tested THC’s impact on ovulation in monkeys. LH levels decreased by a whopping 50 to 80%. This caused ovulation to stop, meaning that the ovary failed to produce an egg.
Something funny happened after about 3 or 4 months, though. Even though the monkeys were still being treated with THC, ovulation and menstruation returned to normal. As tolerance for THC increased, ovulation and menstruation spontaneously began again. A second study examining oral THC administration in rhesus monkeys had similar findings, and those monkeys had no trouble conceiving while under the influence.
In an interview with Vice, Dr. Ricardo Yazigi of the Shady Grove Fertility Center in Maryland explains that:
The risk [of infertility] was greater among women who had used marijuana within a year of trying to become pregnant than among those who had used it in the past, but there was no clear consistency between the frequency and duration of the use with the effect.
But, according to Vice, Dr. Yazigi also articulated:
..it appeared that the effect [on ovulation] was muted in women who used marijuana regularly compared to those who only lit up occasionally, perhaps because regular users had built up a tolerance to the drug.
You may have heard jokes about marijuana causing “slow swimmers” in men, but there may also be some truth to the claim when it comes to newly fertilized ovum in women. A 2006 study published in the Journal for Clinical Investigation found that frequent marijuana use was correlated to slow egg travel from the ovary to the uterus in mice.
Time is of the essence to a fertilized ovum. Once the sperm meets the egg, it needs to implant within a certain period of time before it loses viability. Because marijuana may delay travel, a newly formed embryo may not be able to implant in time to create a pregnancy. An embryo’s failure to implant in the uterus is an “early pregnancy failure” or early miscarriage.
Failure of an embryo to make its proper place in the uterus also increases the risk of ectopic pregnancy. An ectopic pregnancy is when an embryo implants in the fallopian tube rather than the uterus. These pregnancies are extremely painful and risk the life of the mother.
The endocannabinoid system and reproduction
When you use marijuana, active plant compounds known as cannabinoids interact with a network of cell receptors known as the endocannabinoid system. The endocannabinoid system regulates a wide variety of basic bodily functions and helps maintain homeostasis. Homeostasis is a term for the perfect, constant balance inside an organism or a natural environment.
Research has shown that the endocannabinoid system plays a vital role in both male and female reproductive systems. Endocannabinoids and cannabinoid receptors have been found in seminal fluid, as well as in ovaries, fallopian tubes, and the placenta in women. Compounds like anandamide, the body’s natural THC, can kick-start ovulation when levels are high. But, if you want an embryo to implant, low levels of anandamide are a must.
The role of the endocannabinoid system in reproduction is quite complicated. In order for life to form, hormonal and endocannabinoid levels need to be just right at precisely the right time. Any imbalance in the system has the potential to cause unwanted results. Though, exactly what the end result will be is difficult to tell.
THC inside the womb
Apparently leftover THC likes to hang out in fallopian tubes, and this could be damning for sperm cells. While this seems odd, the fact isn’t all that surprising. Endocannabinoid anandamide may be critical for readying sperm for their chance encounter with an egg. Freshly ejaculated sperm cannot be successful without contact with female hormones and sex cells. Anandamide looks like it may be one of them.
A study from 2002 found that there are CB1 receptors on sperm cells. The research found that in low concentrations, anandamide helped the viability of sperm. In high concentrations, anandamide actually prevented sperm from fertilizing an egg. When you smoke marijuana, high concentrations of THC bind to these CB1 receptors, acting similarly to high concentrations of anandamide.
So, does marijuana lead to infertility?
Kind of. But not irreparably. Using marijuana can hinder the process by decreasing viable sperm in men, and it may make getting pregnant a little harder in women. In men, a low sperm count may continue for as long as you keep smoking weed. In women, however, tolerance to the plant over time seems to mitigate some of the initial effects.
The herb might slow things down. But, putting away the vape while you try to conceive seems to get everything back in working order. We can’t say for sure, though, until more advanced clinical research is done in humans.
This list of research is also far from complete. The political debate surrounding marijuana makes the plant difficult to study in general. The social stigma faced by marijuana-loving moms makes examining cannabis use among childbearing women even harder. Much of the human research we’ve seen relies on relatively small sample sizes and self-reporting. Both of these factors hinder the accuracy of what little scientific research we have available.
A Jamaican example
Another major bone to pick with the available cannabis research is where it comes from. Much of the tested scientific information draws heavily from western demographics. People in the United States may have lost their cultural history of using cannabis as a traditional medicine, but many people in Jamaica still use it regularly.
In Jamaica, it’s not uncommon for pregnant mothers to smoke marijuana or drink marijuana tea through pregnancy. After birth, schoolchildren are often given ganja tea, which is believed to promote health and increase academic performance.
Research completed back in the 1980s by Dr. Melanie Dreher followed the pregnancies of 24 marijuana consuming women and compared post-pregnancy results to 20 non-consuming women. The women in the study all had successful pregnancies, and Dr. Dreher’s research found no statistical difference in cognitive or motor development between marijuana-exposed children and non-exposed controls.
Even though cannabis use is the third most popular drug in Jamacia (after tobacco and alcohol), the rate of miscarriages remains more or less on par with the global average. So, while there is evidence that using marijuana may make it more difficult to become pregnant, there are also reports of successful pregnancies and births from marijuana consuming mothers.
There are many reasons why any given person may have trouble conceiving. If you find yourself struggling and frustrated, laying off the herb for a while might help. Though, other factors like stress, diet, and nutrition are also strongly linked to infertility. It’s always best to talk to your doctor to determine what factors are most impacting conception in your individual case. It’s also good to know that just because you’ve smoked weed in the past, doesn’t mean you’ll have permanent fertility issues.
Finally, though science suggests the odds might be stacked against you, getting pregnant while using marijuana is still entirely possible. If you’re hoping to avoid a pregnancy, don’t count on the plant running interference.
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