Malignant ovarian neoplasms during pregnancy are exceedingly rare with an incidence of 1:10000–1:100000 term deliveries. Most women are in their third decade of life at the time of tumor detection. It has been suggested that pregnancy and hormonal manipulations have a protective effect against ovarian cancer. Furthermore, tumors detected during pregnancy are much less likely to be malignant when compared to those not occurring during gestation.

It has been observed that most ovarian neoplasms during pregnancy are detected on routine physical examination during first prenatal visit. In contrast, other authors indicated that the majority of their patients were symptomatic at the time of presentation with abdominal pain, distention or acute intra-abdominal catastrophe such as torsion or rupture. The high frequency of obstetric ultrasound scanning in current practice may increase the detection rate of ovarian tumors during pregnancy. However, it has been shown that such tumors are not infrequently missed, especially in the second and third trimesters, since the growing uterus may conceal large tumors or ovarian neoplasms may not be separated from a cystic enlarged gravid uterus. Although sonography is the primary imaging tool in pregnant women who present with pelvic mass, its specificity is low and many ovarian tumors that do not require intervention are detected. As computed tomography (CT), that uses ionizing radiation, is not desirable during pregnancy, magnetic resonance (MR) imaging can provide supplemental information that may influence patient treatment when results of sonography are equivocal.