Most luteal cysts are physiological, with pathological changes occurring at a certain diameter. In most cases, the corpus luteum begins to shrink 6 to 7 weeks after the last menstrual period and loses function at approximately 10 weeks. However, in about 1 in 10 pregnancies, the corpus luteum does not disappear in the expected time and instead a corpus luteum cyst forms. In general, these cysts are physiological and do not pose a risk to the body. In the pathological state, the corpus luteum is 1.5 to 2.5 cm in diameter and is cystic; if the diameter of the corpus luteum exceeds 2.5 cm, a pathological corpus luteum cyst is formed. If it is large to a certain extent or if the tip twists or ruptures, surgery is considered. Luteinizing cysts are divided into two types according to the origin of the luteinizing cells covering the cyst wall: granular luteinizing cysts and vesicular luteinizing cysts: granular luteinizing cysts: are common, mostly as a consequence of luteinizing hematoma. In the luteal vascularization period, there is a certain limit of bleeding in the luteal cavity under normal circumstances, but in some cases blood can fill the luteal cavity and can form a fairly large hematoma. Vesicular corpus luteum cysts: less common. Most of them occur in association with blistering fetal masses and chorionic carcinoma, but rarely they are complicated by a normal pregnancy. These cysts are seen during pregnancy when chorionic gonadotropin levels are at their highest, and may later degenerate spontaneously. As can be seen, physiological corpus luteum cysts tend to regress spontaneously and should be promptly examined if they cause other symptoms.