Period Syncing: mysticism, science, and the magic of close female relationships
Is period syncing real? A quick google search yields a quick and easy result; allegedly there’s no scientific basis to the commonly held narrative that women’s cycles synchronise when they live in close proximity. Why, despite no substantial evidence, do women themselves often hold fast to their belief in tandem bleeding? This conversation takes us quickly into the realm of magic, human relating and collective phenomena which may lie beyond the capacity of science today. It is one worth having!
Factors affecting Timing and duration of the cycle
Several factors are at play in the duration and timing of the menstrual cycle, and it is quite uncommon to see a completely regular pattern from cycle to cycle. Key players in this regulation are hormones and specific glands, such as the hypothalamus, ovaries, and anterior pituitary [1]. For instance, follicle-stimulating hormone (FSH) is dominant in the first half of the cycle and is responsible for beginning follicle growth and boosting estrogen, while luteinizing hormone (LH) supports egg development and triggers ovulation [2]. In the postovulatory phase the hormone progesterone is produced by the corpus luteum gland in the ovary, whose quality dictates the length of this phase.
The duration of the cycle is most often dictated by the length of the follicular phase, the period from menstruation to ovulation, whereas the luteal phase remains generally stable. Describing a period as “late” or “early” can be misleading. In reality, it usually means that ovulation occurred earlier or later than your typical timing. Tracking when ovulation occurs is a more accurate indicator, therefore, of how regular your cycles are [3].
Period Syncing According to Science
The McClintock Effect, also known as menstrual synchrony, is a hypothesis suggesting that women who live closely together, like roommates or close friends, may experience synchronisation in the timing of their menstrual cycles. It was named after Martha McClintock, a researcher who published a study in 1971 suggesting that women living in close proximity—such as in dormitories—could have menstrual cycles that start to align due to pheromonal cues [4].
The idea is that pheromones, which are chemical signals our bodies emit, might influence the menstrual cycles of others nearby. However, this effect has been the subject of much debate and skepticism over the years. A study published in China in 2006 collected data on menstrual cycles from 186 women living in dorms for over a year. They found that women living in groups did not synchronise their cycles [5].
Researcher Dr. Straussman suggests that menstrual synchrony may be more of a mathematical inevitability than a true biological phenomenon. In simple terms, for a typical 28-day cycle (though this isn’t universal), the farthest apart two women’s cycles can be is 14 days. On average, their cycle start dates would differ by about 7 days, with half the time being even closer. Since menstrual periods often last around 5 days, it’s common for friends to experience overlapping menstruation, which many interpret as personal proof of menstrual synchrony [6].
Historical Period Syncing and Circadian Rhythms
However, while studies have yet to definitively prove that period syncing occurs, I’m all for respecting women’s lived experiences. When women share that their cycles align with their roommates, teammates, or loved ones, it’s hard not to be captivated. Our bodies are powerful and mysterious—so could something else be at play here?
The evidence of ‘pheromonal cues’ is unsupported. However, another interesting suggestion of the Mckintock study is the impact of a shared circadian rhythm on the hormones of women living in close proximity. Mckintock admits that her findings didn’t support this as a significant cause of synchronicity, but the impact of light-dark cycles on the menstrual cycle remains a fascinating inquiry.
Historically, people lived in smaller, close-knit communities where daily routines were synchronised with natural cycles. They often ate similar foods, slept, and woke up according to the sun, exposing them to the same environmental cues. We know the menstrual cycle is influenced by circadian rhythms—the biological patterns regulated by our wake-sleep cycles and light exposure [7].
This could explain why period syncing might have seemed more common historically. When a group of people lives together, their circadian rhythms might influence one another. Also, back then, communities had more shared routines connected to nature’s rhythms, which could have brought about a level of synchronicity that we rarely experience in today’s modern, individualised settings.
Cycle Synchrony, Magic and Mystery
Regardless of the scientific evidence and empirical truth of the matter, the emotional significance of the story of period syncing is compelling. As the saying goes, “Pain shared is pain lessened”, and the emotional bonding and empathy created by the magical feeling of ‘syncing-up’ with female friends could lessen the detrimental effects of cultural menstrual denial, shame and taboo which run rife today [8].
As one researcher puts it; “menstrual synchrony offers one possible avenue to feel collective anger, and it highlights women’s feelings about mysticism, science, and [the magic of] close female relationships.” [9]. For many, myself included, believing in period syncing fortifies the mystical feeling of an innate connection to nature and speaks to a “cosmic structure” that aligns our bodies with the natural ebb and flow of life, linking us with cycles of birth, death, and rebirth.
While science has yet to confirm cycle and period syncing, history, nature, and the powerful stories women share tell a deeper, more mysterious tale. Perhaps, like many other mysteries of life, cycle syncing isn’t something that requires scientific validation to feel true. The real beauty may lie in our ability to connect with nature’s rhythms, and each other.
So, what’s your experience? Have you and your friends ever found yourselves in sync after living or spending a lot of time together? Or do you think it’s all just a myth? Let’s keep the conversation going.
References
- Silberstein, S.D. and Merriam, G.R., 2000. Physiology of the menstrual cycle. Cephalalgia, 20(3), pp.148-154.
- Hafez, E.S.E. and Hafez, B., 2000. Folliculogenesis, egg maturation, and ovulation. Reproduction in farm animals, pp.68-
- Prior, J.C., 2020. Women’s reproductive system as balanced estradiol and progesterone actions—a revolutionary, paradigm-shifting concept in women’s health. Drug Discovery Today: Disease Models, 32, pp.31-40.
- McClintock, M. K. (1971, January 22). Menstrual Synchrony and Suppression. Cambridge, Massachusetts; Department of Psychology, Harvard University.
- Yang, Z., & Schank, J. C. (2006). Women do not synchronize their menstrual cycles. Human nature (Hawthorne, N.Y.), 17(4), 433–447. https://doi.org/10.1007/s12110-006-1005-z
- Beverly I. Strassmann, Menstrual synchrony pheromones: cause for doubt, Human Reproduction, Volume 14, Issue 3, March 1999, Pages 579–580, https://doi.org/10.1093/humrep/14.3.579
- Baker, F.C. and Driver, H.S., 2007. Circadian rhythms, sleep, and the menstrual cycle. Sleep medicine, 8(6), pp.613-622.
- Ray, P., 2022. Do Periods Actually Sync?. Pain.
- Fahs, B., Gonzalez, J., Coursey, R. and Robinson-Cestaro, S., 2014. Cycling together: Menstrual synchrony as a projection of gendered solidarity. Women’s Reproductive Health, 1(2), pp.90-105.
- Kemp, E., 2023. ‘They’re all in sync together’: How the Matildas manage their menstrual health. WAToday (Perth, Australia), pp.NA-NA.
