Of Stress and Periods

One of my college friends spent a year abroad in Australia as a teenager. I was, of course, extraordinarily jealous. However, as we talked more about her experience, she mentioned a very strange side effect of her trip Down Under. While living Sydney she didn’t have her ‘monthly visitor’ for the entire year.  “A whole year?” I said, “Were you ill or something?” To which she replied, “No I wasn’t ill or anything, but I think was just stressed with the move down there and everything, at least that’s what my doctor said.”

As it turns out, my friend is not the only one to experience irregular or skipped menstrual cycles for seemingly strange reasons. In fact, it has long been assumed among doctors and fertility specialists that stress can lead to missed periods. This becomes particularly important with couples who are having problems conceiving. As a result, researchers have conducted countless studies to see if there is a link between stress and ovulation. Some have proposed that psychological counseling may have a positive effect on fertility.

However, the studies themselves have brought mixed results. For example, a 2000 study by Alice Domar and colleagues at Harvard Medical School found a causal link between psychological counseling and increased fertility. Yet another study by Lisbeth Anderheim and colleagues at Gotberg University, also in 2000, found the opposite. Of course periods themselves are slightly mysterious, in that we still don’t really know why humans bother to have them at all.

The mixed results could stem from the difference between psychological stress and physiological stress. It is common knowledge that women who are having physical health problems often stop ovulating; missed periods are a well-known side-effect of anorexia and some forms of cancer. The onset of ovulation can also be affecting by social environments. But what about psychological stress? Can that affect ovulation and fertility as well?

To answer this question, a team of anthropologists at Harvard University, led by Peter Ellison, decided to test women for changes in ovulation who were going through a very stressful time in their lives: preparing for the MCAT. The MCAT, or the Medical College Admission Test, is the exam taken for all those hoping to enter medical school. It takes over nine hours to complete and requires months of preparation. A good score can mean admission into a great medical school. A bad score is doom. A stressful time indeed.

So Ellison examined female juniors at Harvard who were preparing for the MCAT and compared their anxiety levels (and ovulation schedules) to women who were not preparing for the MCAT.  In order to make sure there were no other factors at play, all the women were otherwise physically healthy, were not using any oral contraceptive pill that would change hormone levels, and all reported normal ovulation.

The testing consisted of both sets of subjects completing questionnaires about their perceived stress and anxiety levels, as well as having the subjects monitor their menstrual cycle. In addition, daily saliva samples were taken to test for changes in hormone levels, which are often indicators of physiological stress.

The results were, in many cases, unsurprising. As one would expect, the subjects who were preparing for the MCAT reported an increased level of stress and anxiety leading up to the exam that was much greater than the control subjects. However, this stress seemed purely psychological, as there were no significant changes in hormone levels indicative of physical stress.

But despite the significant increase in stress, there was no change in ovulation or periods in either group. No matter how stressed these students were about the upcoming exam, they continued to have a visit from Aunt Flow right on schedule. This was even the case during the final days and weeks leading up to the MCAT exam, when the subjects described intense stress levels that only Harvard pre-meds can sustain. The study was published in the December 2007 issue of the American Journal of Physical Anthropology.

So what does this mean for the connection between psychological stress and missing periods? According to Ellison’s study, this connection is likely non-existent. As mentioned above, physiological stress that results from malnutrition, or even extreme anxiety levels that occur during life-threatening situations, could lead to changes in ovulation, says Ellison. But it would seem that otherwise healthy individuals cannot automatically claim that ‘stress’ is the cause of their continued missed periods; there must be some other physical cause.

As for my friend who traveled to Australia, I can only speculate that there was some other explanation for her missed periods…probably having to do with everything being upside down in the southern hemisphere.