The image shows a graph with hormone levels on the vertical (y) axis and days 1 – 28 on the horizontal (x) axis. The graph shows the first phase is early follicular phase then the late follicular phase, next is ovulation at 14 days. After ovulation is the mid luteal phase and the late luteal phase. The hormone oestrogen is represented in light blue and it rises up to 12 days before falling around ovulation. It rises again after ovulation to peak at the mid luteal phase and then fall towards the end of the 28 day cycle. The hormone progesterone is represented in dark blue and it stays low up to 12 days before rising around ovulation. It keeps rising again after ovulation to peak at the mid luteal phase and then fall towards the end of the 28 day cycle.