Most women have either heard of or experienced the phenomenon of bleeding in synch with their fellow sisters. But what causes it? And how does it affect your fertility?
There is very little scientific research on this topic so it is difficult to arrive at one definitive answer. It is probably a combination of factors that has changed and evolved over the centuries.
Think back to when we lived tribally thousands of years ago with no artificial lighting. In these natural surroundings it was highly probable that women ovulated together on the full moon and bled on the dark moon. Thus they usually gave birth at the Full moon, creating more individuals with this particular lunar fertility blueprint.
This model for the menstrual cycle is traditionally offerred as the most common because it was the norm for thousands of years. I speak of this in the Fertility Freedom ebook, the theory that this model of cycling offers the most positive chances for physical fertility based on the rising and falling energy of the moon throughout the month.
But of course these days, we live in the world of artificial light. We no longer are born just on Full moons - but on every phase and degree in the whole cycle. What effect does menstrual synchrony have on our own personal lunar blueprint? If your natural lunar fertile time is the first quarter what happens when you start getting in synch with women who ovulate at the third quarter? Using the theories of lunar fertility - you would have two fertile times a month instead of one. In this way synchronisation to other women may not be of benefit. But what if you are having trouble conceiving or suffer irregularity? Hanging out with pregnant women or synchronising to regular women could have positive effects on your cycle outweighing the benefit of being in tune to your own individual rhtythm.
Women also cycled together for the benefit of the tribe. Consider the practise of the Moonhut in some native cultures. At bleeding, women would gather together away from other members of the tribe to meditate, pray and receive guidance. Women doing this work together would have made this time more powerful due to thier combined collective energy. When their bleeding was over, these women would return to the tribe and offer guidance and advice based on their experiences. In this case it was more powerful for women to cycle together.
What about physical fertility and survival? In a tribal environment - people have to cooperate for the success of the tribe. If women are having babies together they can support and help each other through that time. For example if one mother becomes ill and could not nurse her child, another new mother could take over feeding her baby. Martha McClintock sites studies on pheromones and rats that point to this survival mechanism in humans.
http://www.abc.net.au/radionational/programs/healthreport/menstrual-synchrony/3552148 Article by Martha McClintock
Of course in modern society we live in a less tribally and more isolated way. Women now often live in nuclear families and certainly don't seem to have the experience with extended family/tribal living that they used to. In some ways our survival is less dependant upon the women around us than the men around us.
But it would appear that our bodies still respond to this instintive cue to cycle together. When groups of women live together, work together or play together, if we have good friends that give us emotional support then these are the women we will synchronise to.
It would seem menstrual synchrony is some sort of survival mechanism for women. Women are naturally group or tribal minded. We relate to each other in very different ways to the ways men relate. I remember reading a book on female intelligence ( The First Sex by Helen Fisher) that spoke of the ways the female brain is wired, the way we behave and operate to stay connected and gain the approval of our female tribe members. Being cast out was akin to death. Could it be that cycling together protected our marraiges and social bonds? Perhaps if we were all fertile at the same time it lessened the chance of infidelity resulting in more children than the tribe could care for or children that the tribe would reject for cultural or social reasons.
Written by Nadia MacLeod