Inkling has an interesting article on the effect of stress on the menstrual cycle that investigates the received wisdom that stress can prevent periods.
It turns out the scientific studies have found no conclusive answer as they’ve returned mixed results, but this may be because they don’t adequately distinguish between physical stress and psychological stress.
A range of physical health problems are known to halt menstruation. Malnutrition is a common example and this is why women with anorexia often don’t have periods.
Of course, physical and psychological stress go hand in hand, but one study that looked at healthy young women under a great deal of psychological stress, but no major physical health problems, found no alteration in the menstrual cycle.
So Ellison examined female juniors at Harvard who were preparing for the MCAT [Medical College Admission Test] 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…
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.