Menstruationszyklus, synchroner Zyklus

Of blood sisters and cycle friendships

By Susan Reznik (text) & Silja Elsener (illustration)

Whether it’s with your roommate, formerly with your mother and sister, your partner or with a friend with whom you’ve been traveling for a long time: suddenly your menstrual cycles adjust. As if the physical and emotional proximity would also bring your biorhythms together. Already experienced?

Myth of coincidence or some cosmic and energetic connection of female primal power? Or evolutionary miracle? First of all: To this day, no one knows for sure and science has very different opinions on this.


The trailblazer

A pioneer who got to the bottom of this question in the 1970s is Marta McClintock. Ten years earlier, when she was still a psychology student, she had been investigating how pheromones could control ovulation in mice. Pheromones are so-called sex attractants that are perceived subconsciously. Of course, it was also obvious to investigate whether this could also affect humans. So in 1971 McClintock studied 135 female students at Wellesley College in Massachusetts for her period synchronization hypothesis. The result of their research: The cycles of roommates synchronized more strongly than those between girlfriends who did not live together.

McClintock came to this conclusion when surveys showed that female students menstruated six and a half days apart after the summer semester break. During the semester, about seven months after the holidays, it was only four and a half days apart. In the control group, consisting of randomly selected unconnected women, the ten-day interval remained constant. Other voices in science, however, believe that this observation is just a coincidence caused by mathematics.


Coincidence or not?

Over the past few decades, various studies have been conducted on this subject involving women from a West African tribe who live together in huts during their period. Also with lesbian couples, as well as athletes from a basketball team. However, there were no clear results on a synchronization effect. In order for it to be really accurate, women would have to be examined who all have a consistently equal cycle length.

In the end, we think it doesn't really matter whether it's a coincidence or not. It's much more important how we can use the time together and connect together when we're menstruating at the same time. For example, by talking about our period and not being alone with it. Or watch a film together with lots of good soul food and a warm bed bottle. Toast the blood friendship with a cup of soothing tea and rub each other's bellies with BLUE TEARS . Just knowing that we are not alone with our period can be very healing.

blood sisters

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