Evaluation of the fetus using prenatal ultrasound has resulted in increased detection of asymptomatic adnexal masses during pregnancy. Such masses are rarely malignant (1/10 000 to 1/50 000 pregnancies), but the possibility of borderline or cancer must be considered. It is a common assumption by both patients and physicians that if an ovarian cancer is diagnosed during pregnancy, treatment necessitates sacrificing the well-being of the fetus. However, in most cases, it is possible to offer appropriate treatment to the mother without placing the fetus at serious risk. The care of a pregnant woman with cancer involves evaluation of sometimes competing maternal and fetal risks and benefits. These recommendation approaches attempt to balance these risks and benefits; however, they should be considered advisory and should not replace specific interdisciplinary consultation with specialists in maternal-fetal medicine, gynecologic oncology, and pediatrics, as well as imaging and pathology, as needed. Second level ultrasound including Doppler is needed. MRI is not often necessary, and CA 125 is of low contribution. We suggest surgery be performed after 15 SA for ovarian masses which (1) persist into the second trimester, (2) are greater than 5 to 10 cm in diameter, or (3) have solid or mixed solid and cystic ultrasound characteristics. During antepartum surgical staging and debulking, homolateral salpingo-oophorectomy and peritoneal cytology and exploration are necessary. Women found to have advanced stage epithelial ovarian cancer should consider having completion of the debulking of the reproductive organs at the conclusion of the pregnancy. If chemotherapy is indicated, we recommend delaying administration, if possible, after the delivery or at least after 20 SA in order to minimize the potential fetal toxicity.