Of blood sisters and cycle friendships

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

Whether with your roommate, previously with your mother and sister, your partner or with a friend with whom you are traveling for a longer period of time: suddenly your menstrual cycles adapt. As if the spatial and emotional proximity would also bring your biorhythms together. Already experienced it?

Myth of chance or some cosmic and energetic connection of primal feminine power? Or evolutionary miracle? One thing first: To this day, no one knows for sure and scientists have very different opinions on it.

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 investigated the possible control of ovulation by pheromones in mice. Pheromones are so-called sexual attractants that are perceived unconsciously. Of course, it also made sense to investigate whether this could also affect people. 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 friends 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, there were only four and a half days apart. In the control group, consisting of randomly selected women without a connection, the interval of ten days remained constant. However, other voices in science believe that this observation is just a coincidence that is mathematically determined.

Coincidence or not?

Over the last few decades, various studies have been carried out on this topic with women from a West African tribe who live together in huts during their periods. Also with lesbian couples and athletes on a basketball team. However, there were no clear results for a synchronization effect. In order for it to be really accurately recorded, women would have to be examined who all have a consistently equal cycle length.

We think that in the end it doesn't matter much whether it's coincidence or not. What is more important is how we can use the time together and bond together when we menstruate at the same time. For example, by talking about our periods and not being alone about it. Or watch a film together with lots of good soul food and a warm bedtime bottle. Toast to your blood friendship with cozy tea and rub each other's bellies with BLAUE TRÄNEN. Just knowing that we are not alone with our periods can be very healing.