When woman are on their cycle, it is recommended that they do not invert. Why?

Gravity plays with our bodies in yoga, in fact we encourage classes like gravity surfing.
When we enter our menstrual cycle and invert we are not always at risk but the umbrella
is held in place for bodytypes which it might increase risk. The uterus can stretch when we do inversions allowing for more blood flow to accumulate causing heavier flow. If there are already preexisting genetic defects or conditions this can cause unnecessary stress on the body during a sensitive time. There are many stretches you can do to alleviate the pressure and cramps like forward bends , twists and supported standing poses.