We report two cases of a rare pathology of the fetal cerebellum, rhomboencephalosynapsis, a defect characterized by the partial or complete absence of the cerebellar vermis, which is currently associated with severe ventriculomegaly due to defects in the formation of the cerebral aqueduct. These are the first cases reported in Peru.

Multiple gestation pregnancy rates have increased in recent years possibly related to socio-demographic factors including deferral of motherhood and some medical factors like fertility treatments. Associated complications including prematurity, cerebral palsy, hypertensive disease of pregnancy, hyperemesis, gestational diabetes have also increased.