Abstract
Mucinous cystadenoma (MC) of the ovary is an unilateral, multilocular cystic benign epithelial tumor. Supposed to be hormone responsive, MC reaches huge sizes during pregnancy. Aortocaval compression is common during pregnancy, especially when the pregnant woman is in the supine position. However, the compression recovers with a change in position. The authors report the first case of a huge mucinous cystadenoma of the ovary complicating pregnancy and causing virilization, premature labor, and persistent supine hypotensive syndrome.