There are all sorts of physiological phenomena in the body that are worthy of study, but the menstrual cycle is one of the most intriguing from a bio-sociological perspective. It's well understood that women's cycles can affect one another, and many environmental factors can also affect a menstrual cycle. Beyond that, it's been historically established in many studies that marijuana use can impinge on both male and female fertility as well as the menstrual cycle. New research now suggests that the presupposed effects of marijuana don't even actually apply.

Here at EQW, we recently published an in-depth look at pheromones and busted the myth that human pheromones can be used to make a person more attractive to the opposite sex. We actually found several things wrong with that perspective; suffice it to say that scientific data doesn't support that notion. We ultimately found that there may not even be such a thing as a human pheromone — not going by the original definition of the term anyway. That being said, the story did deal with the closest thing to human pheromones known to exist, and what legitimate scientific data back in the '80s suggested was the human equivalent to pheromones is, instead, a mechanism that influences women's menstrual cycles.

Back in 1986, The Washington Post published an article covering a scientific study that came out of Philadelphia. The study found that human bodies do produce these aromatic chemical compounds that influence other humans' sexual physiology. Loosely speaking, that definition can be attributed to animal pheromones, too, but what this study actually meant was a lot different than what we tend to think. Chiefly, these so-called pheromones don't take instant effect but, rather, take effect very gradually and imperceptibly over time; moreover, they have nothing to do with sexual attraction. Over the course of weeks or even months, these chemical compounds directly change the timing of women's cycles.

Pseudo-pheromones aren't the only thing to have this effect on menstrual cycles, though, and it's becoming increasingly common knowledge that, at the very least, women shouldn't panic if they don't get their period every 28 days because of the sheer scope of things that can affect the cycle. Some might wonder if another myth worth busting is that weather affects cycles, but research confirms that it's not a myth. Experts just published a study in the medical science journal, Gynecol Endocrinol, and found that just sunshine itself (or a lack of sunshine to the same degree) can alter the length of one's periods.

Earlier this month, Dr. A. Nicky Hjort and his colleagues found that "in summer vs. winter, there was a trend toward increased FSH secretion, significantly larger ovarian follicle size, higher frequency of ovulation (97 percent vs. 71 percent) and a shorter menstrual cycle (by 0.9 days)." The study went on to say, "Ovarian activity is greater in summer vs. winter in women living in a continental climate at temperate latitudes; [and] sunshine is a factor that influences menstrual cycle."

Additionally, climates that have more extreme seasonal shifts tend to cause people to make lifestyle changes with each coming season that are highly likely to change their cycles. This speaks to a rather common complaint in many areas from people who say that their periods are worse in the winter. Hjort, the lead author on the study, says, "When it's nice out, we also tend to spend more time outdoors and more time moving. Women who exercise regularly, and who have a higher level of fitness, are less likely to suffer from a severe form of PMS, a.k.a. premenstrual dysphoric disorder (PMDD), and are less likely to have heavy and irregular menstrual bleeding."

The latest bizarre revelation about what does and does not affect the menstrual cycle, though, has to do with marijuana. A new study is challenging the preconceived theory that marijuana use impinges on both male and female fertility as well as on menstrual cycles. Published in the Journal of Epidemiology and Community Health, the study finds that there's actually no correlation between marijuana use and fecundability, which is a couple's average probability of conceiving during any one menstrual cycle. That correlation has, for a long time now, been the primary basis for the scientific theory that marijuana hurts fertility and the chances of conception.

"Given the increasing number of states legalizing recreational marijuana across the nation," says Lauren Wise, alluding to the nine states nationwide to have legalized it for recreational use, "we thought it was an opportune time to investigate the association between marijuana use and fertility." Wise is a Boston University professor in the College of Public Health, and she's the lead author on this new study. The research suggests that the problem with previous studies is multifaceted. One facet is that they were animal studies and not clinical trials. Those studies also indicated that marijuana drove up miscarriage susceptibility if used during early stages of pregnancy. Also, they were strictly focused on actually smoking marijuana, which is hardly the only method of intake.

This study was an actual clinical trial with 4,194 female participants between the ages of 21 and 45, and all were either U.S. or Canadian citizens. The study was conducted for four years from 2013 to 2017. Wise and her team surveyed them and conducted 12 rounds of follow-ups, and they found that conception probabilities weren't meaningfully different between couples who used marijuana and couples who didn't — before, during and after the menstrual cycle.

[researchpaper 리서치페이퍼=​Cedric Dent 기자]