Figure 25. Placenta of monoamnionic twins following death of one twin in utero. The second twin was delivered at 36 weeks. At 28 weeks fetal death of the sibling with velamentous cord insertion was noted. The other baby appeared stable, and the pregnancy continued. However, head circumference plateaued. At birth the living sibling had complete hydranenecephaly. Velamentously inserted cords are vulnerable to mechanical compression independent of multiple gestation, but may be a bigger problem in multiple gestation due to intrauterine crowding.