Written by: Areesha Ahmed
The year 1971 saw the birth of a fascinating and almost mystical menstrual theory in the form of the “McClintock Effect” or “Menstrual Synchrony”. Stemming from an extensive paper published in the British journal Nature, the research was conducted by an undergrad student named Martha McClintock. The results, based on observations of 135 Wellesley College students, showed that close friends in a dormitory were menstruating at the same time every month. This hypothesis also suggested that pheromones or other factors can influence and shift periods for menstruators who live in close proximity to each other.
Afterward, many researchers came forward with results that period syncing is not an actual phenomenon and most people’s experiences can be attributed to coincidence rather than pheromones. Deliberate syncing is almost impossible because every person’s period cycle is unique to their body and no two bodies have a similar working.
While McClintock’s paper was the first-ever scientific study on syncing, the idea of similar cycles is a part of many cultures with most menstruators swearing on having synced up with their parents, siblings, partners, close friends, or roommates. Likewise, I too can say that after having lived with my roommate for years, there are more instances where I recall syncing with her than not. So the question remains that if not scientific, then what is really happening? The answer lies in not science but basic maths: Over time, a menstruator with a three-week cycle and another with a five-week cycle will eventually see their periods coincide and diverge again.
Like most myths related to menstruation, period syncing is also one that makes it seem like the uterus indeed has magical powers of its own and can inexplicably influence others’ bleeding cycles. Fortunately for us, the concept of synchrony is quite unlike other myths and taboos surrounding menstruation. It does not add an element of shame, repulsion, or seclusion to the physiological phenomena and rather introduces a feeling of “period solidarity” among menstruators while also strengthening relationships on account of shared experiences.