Hello, Ovarian cysts are sometimes discovered during pregnancy. In most cases, they are an incidental finding at the time of routine prenatal ultrasound screening. The majority of ovarian cysts found during pregnancy are benign conditions that do not require surgical intervention. However, surgery may be indicated if there is a suspicion of malignancy. rupture or torsion (twisting of the cyst, disrupting the blood supply)are the acute complication, bigger the size chances of complications are higher, that time you need surgical intervention,,, otherwise it won't affect you or your baby. Get your antenatal checkups done regularly.