Meditation is the best practice to perform during menstruation. Women should refrain from mantras, vocalizations, and transmutation at this time, because this circulates energy while the body is cleansing itself. Comprehension in meditation can always be cultivated, however, no matter the circumstances.
For thirty years I sought God. But when I looked carefully I found that in reality God was the seeker and I the sought. -Bayazid al-Bastami