Triploidy in a twin pregnancy: small placenta volume as an early sonographical marker.

Introduction: We report a case of a twin pregnancy with triploidy of maternal phenotype of one foetus and no chromosomal anomaly of the other twin and the role of sonographical placental volumetry.

Case: At 12 weeks of gestation, a dichorionic twin pregnancy discordant in growth is diagnosed. 3D ultrasound reveals a distinctly small placental volume of foetus II.