Ultrasound examination, both pre- and postnatal, has made it possible for clinicians to recognize perinatal ovarian cysts and other intra-abdominal masses for decades. True neoplasms are rare, simple ovarian cysts are common, and large or complex cysts often demand surgical attention. A variety of approaches including aspiration (both pre- and postnatal), surgical removal, or observation have been proposed and are acceptable depending on the radiographic and clinical circumstances.