Monosomy X Yolimar Martinez, MD Article Published: Feb 11, 2005 These are the ultrasound scans of a fetus at 14.3 weeks of gestation. A complete atrioventricular canal, truncus arteriosus and cystic hygroma were present. An amniocentesis revealed 45 X0. Cystic hygroma: Complete atrioventricular canal and truncus arteriosus:  Fetal biometry: Discussion Board Start a discussion about this article Add bookmark Bookmarked