Assessment for aneuploidy is an important aspect in the evaluation of abnormalities in any pregnancy, singleton or multiple following in vitro fertilization. As in singleton pregnancies, when there are maternal agerelated risks, abnormal first- or second-trimester screening, or the finding of congenital anomalies, definitive fetal karyotype assessment is often requested in multiple gestation. Both amniocentesis and chorionic villus sampling can be safely accomplished in multiple gestation. Multifetal pregnancy reduction (MPR) and selective termination (ST) are techniques developed in an attempt to decrease specific risks from multiple gestation. The use of ultrasound in pregnancy can be divided into four main categories: growth evaluation, Doppler velocimetry, cervical length evaluation, and antenatal testing. Ultrasound assessment is considered an essential component in the intrapartum management of these pregnancies. If a nonvertex second twin version is needed, ultrasound monitoring enhances the safety of the procedure.