Does a corpus cyst mean you got pregnant?

No. A corpus luteum cyst is an ovarian cyst that may rupture around menstruation. It may take up to 3 months to disappear, and they are least likely to appear in women over 50. Such a cyst may grow up to 4 inches long. It may bleed into itself, possibly twisting the ovary and causing pain. In a worst case scenario, such a cyst can twist the ovary enough to cause ovarian torsion, meaning that the blood supply to the ovary in question is getting choked off. That could become a medical emergency.

When an egg cell is released from a follicle, the follicle turns into a secretory gland called the corpus luteum (literally, "yellow body"). Its job is to release estrogen and progesterone in preparation for pregnancy. If there is no pregnancy, then usually, the corpus is supposed to break down and disappear. But if things get complicated and the corpus luteum fills with blood or other fluid, then a cyst occurs. Most of the time, the cyst is on only one side and doesn't cause symptoms.