If you don't know how this works or forgot you need to have this awareness when you begin a natural hormone treatment program. I searched for a long time to find an over the counter Bio-Identical cream that was organic. Check it out here on this board.
The ring of fire sign also known as ring of vascularity signifies a hypervascular lesion with peripheral vascularity on colour or pulsed doppler examination of pelvis due to low impedance high diastolic flow 1. This sign can be seen in highly vascular pelvic lesions like: corpus luteum cyst (more commonly) ectopic pregnancy http://radiopaedia.org/articles/ring-of-fire-sign
Hypothalamic-pituitary cycle. FSH: Stimulates development of ovarian follicles. LH: Stimulates the follicle to release the ovum. Gn-RH: Stimulates the release of the hormones FSH and LH from the pituitary. Estrogen & Progesterone: Falling levels of these 2 hormones stimulate the hypothalamus. Corpus Luteum: Post-ovulation follicle develops into "yellow body" that produces progesterone and some estrogen.
This chart shows the progression of the follicle/corpus luteum, body temperature, hormone levels, and the building of the uterine lining during an average female cycle. Ovulation is marked by the grey vertical line.