During a woman's menstrual cycle, ovarian cyst formation is normal. These cysts are part of developing an egg to ovulate or to make hormones to support a potential early pregnancy, and are called functional cysts. These type of cysts should disappear with each cycle. I get worried that a cyst is abnormal if it persists for more than 2 cycles, if it is larger than 5 cm, or if it has unusual features such as a septum or solid elements. Sometimes a functional cyst can cause severe pain and internal bleeding if it should rupture internally. This is usually an emergent situation that requires immediate evaluation.   _{Your Comment}