George writes that it is here, at the dark of the moon, that "life cleanses, revitalizes, and transforms itself in its evolutionary development, spiraling toward attunement with its essential nature". Studies have shown that most women begin their menstrual periods during the dark of the moon (new moon) and begin bleeding between four and six A.M. - the darkest part of the day.
If we do not become biologically pregnant at ovulation, we move into the second half of the cycle, the luteal phase - ovulation through the onset of menstration. During this phase, we quite naturally retreat from outward activity to a more reflective mode. During the luteal phase we turn more inward, preparing to develop or give birth to something that comes from deep within ourselves. Society is not nearly as keen on this as it is on the follicular phase. Thus we judge our premenstrual energy, emotions, and inward moods as "bad and unproductive."
Since our culture generally appreciates only what we understand rationally, many women tend to block at every opportunity the flow of unconscious "lunar" information that comes to them premenstrually or during the menstrual cycle. Lunar information is reflective and intuitive. It comes to us in our dreams, our emotions, and our hungers. It comes under the cover of darkness.
- page 100 of Women's Bodies, Women's Wisdom