Multifetal gestations account for 2–4% of all pregnancies and have increased remarkably since the 1980s. The rise is largely due to an increasing maternal age and scientific advances in assisted-reproductive technology. Multifetal gestations pose pregnancy risks in higher amounts than their singleton counterparts. Prematurity, and its sequelae, accounts for a significant contribution to both fetal and maternal morbidity and mortality. An understanding of twin biology and early recognition of chorionicity is essential to the management of multifetal gestations.