What are the hormones that control menstruation and when are they needed?
The group of oestrogens and progesterone are the two involved. In a normal cycle the level of oestrogens rise, peaking at around day 12, normally resulting in the release of an egg from the ovary. Levels of this hormone group gradually drop over the next few days and at the same time the progesterone levels rise. If the egg is fertilized then progesterone levels continue to rise but if there is no fertilization within 10-12 days after ovulation, then both progesterone and the levels of oestrogens subside resulting in the onset of menstruation.
