Debunking myths; can our periods really synchronise?

The though of syncing your menstrual cycle with another in close proximity has long been a subject of intrigue and curiosity and sometimes longing!.  Many have heard stories or even experienced firsthand the alleged phenomenon of periods aligning among women who spend significant time together. But is there any truth to this widely accepted belief? Let's explore the science behind it.


The McClintock Effect.

The idea that women's menstrual cycles synchronise is often referred to as the "McClintock effect," named after researcher Martha McClintock. In the early 1970s, McClintock published a study that seemed to support the concept of menstrual synchronisation. However, subsequent research and more rigorous studies have failed to replicate her findings, casting doubt on the existence of this phenomenon.

Several large-scale studies conducted in recent years have challenged the very notion that we can align with our sisters. One such study, published in the journal Human Nature in 2013, analysed over 360 pairs of women living together and found no evidence of synchronisation. Similarly, a comprehensive review published in the journal Women's Reproductive Health in 2017 concluded that any existing  evidence in support of the myth was both weak and inconsistent.

The hormone effect.

Menstrual cycles are regulated by complex hormonal interactions within the body. While these hormones can be influenced by external factors such as stress, pheromones, or social interaction, there is no conclusive evidence that they lead to periods syncing. In fact, studies have shown that the variations in individual cycle lengths and the hormonal patterns of women are too diverse to support the notion.

Confirmation bias.

The belief in menstrual harmony with another is often fuelled by confirmation bias, where instances of periods aligning among women are remembered and reinforced, while instances that do not align are overlooked or forgotten. This selective recall can contribute to the perpetuation of the myth, even in the absence of scientific evidence.

That said, would like to believe it has happened to me over the years.  It has like a secret and celebrated bond of sisterhood.  So despite the evidence to the contrary, I am choosing to continue believing!


Have a look at our other POP TALK blogs.

💋  To flush or not to flush?

💋  How International Women's Day all began 

💋  What it single use period plastic?

💋  What is Period Poverty?

💋  Why does my poop change when I have my period?  

💋 What is Menstrual Hygiene Day all about?

Together, we can work towards a more sustainable and eco-friendly future for all.