Ultrasound in the evaluation of twin pregnancy.

Multiple gestations account for approximately 3% of all live births, but contribute to a disproportionate 15% of the overall perinatal mortality. Ultrasound evaluation of twin pregnancies serves an important role in surveillance, early detection, and invasive treatment of complications in twin pregnancies, including spontaneous abortion, abnormalities in placentation, preterm labor, growth restriction, congenital abnormalities, fetal demise, fetal mal-presentation, and twin-to-twin transfusion syndrome. A review of literature regarding the indications and use of ultrasound in twin pregnancy is presented.