Whether ovarian cysts have an effect on the fetus, there are three main aspects to consider, as follows: a. Nature of ovarian cysts: benign ovarian cysts generally have very little effect on the fetus, while malignant or junctional cysts need to be treated, and if necessary, abortion and induction of labor need to be done, followed by surgical treatment. The size of ovarian cysts: 1. benign ovarian cysts less than 5cm: generally considered physiological possibility, without any treatment, regular observation is possible. If the cyst does not increase or disappear during pregnancy, it will not affect the fetus. If it gradually increases and gets bigger, consider the possibility of malignant change or the possibility of torsion or rupture, and it should be treated in time. 2. Ovarian cysts larger than 5 cm: they should be observed regularly and closely, and pregnant women should be instructed to avoid strenuous activities throughout pregnancy. If there is severe abdominal pain, go to the hospital in time because there is a high possibility of torsion or rupture in this case. Third, the changing situation during pregnancy: If it is a huge ovarian cyst, it must be dealt with because during pregnancy as the fetus grows, the space in the abdomen will gradually shrink, so the cyst will appear to be under pressure and rupture, and it is usually removed surgically around the fourth month of pregnancy.