Figure 3. This is a placenta from a TTTS pregnancy that was lost at 21 weeks’ gestation before any treatment could be started. Both twins had umbilical cords that were velamentous and attached at opposite ends of the placenta. The twins had multiple vascular connections between them (mostly artery-to-vein), but these connected in a vascular equator (arrows) that was off-center resulting in asymmetrical sharing (80% vs. 20%) of the placenta by the twins. (Photo courtesy of Dr. Julian E. De Lia)