**4. Surveillance**

Surveillance in multiple pregnancies has a significant importance, as it plays the major role in the detection of complications that are associated with a high-risk pregnancy, and it is well known that multiple pregnancy is a classic example of a high-risk pregnancy. However, the appropriate frequency of the ultrasound assessment in both dichorionic and monochorionic pregnancies, which provides the best balance between cost and effectiveness, is not be established and worldwide accepted [3].
