On abdominal examination you may notice that:

• The size of the uterus is larger than the expected for the period for gestation.
• The uterus looks round and broad, and fetal movement may be seen over a large area. (The shape of the uterus at term in a singleton pregnancy in the vertex presentation appears heart-shaped rounder at the top and narrower at the bottom.)
• Two heads can be felt.
• Two fetal heart beats may be heard if two people listen at the same time, and they can detect at least 10 beats different (Figure 8.6).
• Ultrasound examination can make an absolute diagnosis of twin pregnancy.