A friend recently asked me why women are advised not to do inversions if they are on their period. I explained briefly that it’s mainly because when we’re standing upright the blood flow is down and out, but when we’re inverted the blood is then going the other way. Judith Lasater explains it slightly better than me by saying “a pose is considered inverted if the uterus, or lower abdominal region, is higher than the heart. Even poses that elevate the legs above the level of the heart should be avoided”. (Judith Lasater in Relax and Renew, p.158)
Traditionally, yoga was done only by men so this would not have been an issue. The feminist is me regards the ‘no inversions on your period’ stance partly as a slightly patronising approach portraying women as weaker and unable to do everything. However, there may be valid reasons to listen to this advice.
In yogic terms there are five winds of prana (the life force) called vayus. One of these is called apana and it controls various downward flows from the navel including urination and menstruation. In some pranayama techniques the intention is to force apana upwards (for reasons I won’t go into right now), but if this apana is forced upwards during menstruation it can adversely affect menstruation (Sharon Gannon and David Life in Jivamukti Yoga, p.104). They go on to advise not doing strong asana or pranayama for a couple of days if menstruating.
Judith Lasater explains both this apana reasoning and the Western body approach by explaining that gravity causes the blood vessels supplying the uterus to be blocked by the weight of the uterus dropping down when inverted, which can cause the menstrual flow to pause/stop for several hours, and then resume more heavily. She has devised a ‘Moon club’ sequence of postures to help with cramps, back discomfort and quieting during this time.
In Ashtanga yoga for women Sally Griffyn and Michaela Clarke say: “Menstruation was considered in ancient cultures to be a time of great internal power and wisdom. It was a time for women to retreat from their daily activities and use their energy to do spiritual practices.” (p.114). That sounds really good! In contrast, I see it as a bane to get through each month. Interestingly, in Ashtanga yoga, the formal position is that there’s no classes on full or new moon days because of the pull of energy from one kind of energy in the waning phase to another in the waxing phase (p.112), and so if a woman’s monthly cycle is in harmony with the lunar cycle and she’s menstruating at either the full or new moon, she would be resting anyway.
For myself I find that on the first couple of days of a period I generally wouldn’t feel like doing an inversion, but after that, I feel fine and happy to do headstands, shoulder stands, downward facing dog etc. My approach therefore is very much that each woman should listen to her own body, and every month may well be different. In classes I give the instruction not to do an inversion if you are menstruating and don’t feel like doing it. That way each woman can decide for herself.
Update 5th October 2015
In reviewing reading around menstruation and yoga, I came across a new article referencing scientific research on women and periods, published in 2014. In it the author argues that whilst the apana situation may well be true, there is no evidence of inversions during menstruation causing endometriosis. The article presents the findings relatively simply and is worth a read. My advice stays the same – you do what you feel like.