A cyst of 15 cm in the 6th month of pregnancy is likely to rupture. The presence of cysts in women generally refers to ovarian cysts, and when the uterus has increased above the level of the navel in the 6th month of pregnancy, ovarian cysts are prone to rupture due to compression of the uterus and abdominal wall, especially when the abdomen of a pregnant woman is squeezed or hit by external forces, which may increase the risk of rupture of ovarian cysts. Therefore, if a woman has ovarian cysts during pregnancy, especially if she has large ovarian cysts, she needs to minimize the compression and impact on the abdominal wall and pay attention to her safety. Ovarian cysts can be of different nature. In case of rupture of a simple ovarian cyst, it may cause abdominal pain and other symptoms, but the fluid inside the cyst is usually less irritating to the peritoneum and can be treated by proper observation and does not necessarily require emergency surgical treatment. In the case of ovarian endometriotic cysts, i.e. ovarian chocolate cysts, the rupture of ovarian endometriotic cysts may require surgical treatment in the event of rupture due to the presence of large amounts of accumulated blood within the cyst and the inflow of stale blood into the pelvic and abdominal cavities, which can strongly irritate the pelvic peritoneum, resulting in symptoms of peritoneal irritation such as severe abdominal pain and abdominal muscle tension, and may even result in continuous bleeding. In addition to ovarian cysts, rupture may also occur if a woman has intrapelvic cysts such as intravaginal cysts, intrauterine cysts, cervical cysts, fallopian tube cysts, and round ligament cysts in the uterus, 15 cm cysts that are compressed by a larger uterus in the sixth month of pregnancy. If a woman has abdominal cysts such as liver cysts and pancreatic cysts, 15 cm cysts are larger and are prone to rupture under the pressure of an expanding uterus and usually need to be surgically removed. Once the symptoms of ruptured ovarian cysts such as abdominal pain occur, pregnant women need to go to the hospital promptly. 6 months of pregnancy is the middle of pregnancy, and if treatment by surgery is necessary at this time, surgery can be performed at this gestational week. Pregnant women should still pay more attention in general and try to avoid possible risk factors that could lead to ovarian cyst rupture, after all, there are certain risks whenever surgery is performed during pregnancy.