If the cyst is benign and small, there is usually no effect on the fetus. The pregnancy can continue. Wait until after delivery and then observe. This is because there is a type of post-pregnancy cyst that is functional and arises with conception and disappears with delivery. Therefore, it should be observed after delivery. If it does not subside and has a tendency to increase in size, surgical removal may be considered. Do ovarian cysts affect fertility? During pregnancy, some cysts may rupture and twist, and there will be more intense abdominal pain, which should be treated promptly by a doctor. If the cyst, especially if the review after menstruation is clean, is above 5 cm, the patient is advised to clarify whether the cyst is benign or malignant and it is best to remove the cyst before pregnancy. Otherwise, if the nature of the cyst is not clarified before pregnancy, it will be detrimental to the future health if it is malignant. Even if a benign cyst is large, it may rupture during pregnancy and cause problems of acute abdomen during pregnancy. It is better for the patient to have the nature of the ovarian cyst, its size and the need for surgery checked before pregnancy. Some ovarian cysts may cause miscarriage in early pregnancies, and in mid-term pregnancies, they may cause torsion of the ovarian cyst. The pelvic congestion during pregnancy may cause the tumor to increase rapidly and may even cause malignancy, thus pre-pregnancy surgery is more beneficial than pregnancy surgery. If you are already pregnant, surgery at 16-24 weeks of gestation is appropriate. The surgery itself does not affect the development of the fetus, but surgery within 12 weeks of gestation is likely to cause miscarriage, while surgery in late pregnancy is more difficult and likely to cause preterm delivery. Of course, emergencies such as cyst torsion or rupture are a different story and should be treated with surgery at any time.