They decided to see whether the height of the uterus, as measured by transvaginal ultrasound (a process called hysterosonometry or HSM) could predict the outcome of twin pregnancies after IVF.

• 他们决定观察是否由经阴道超声（子宫超声检测或HSM）测量的子宫长度能否预测IVF后双胎结局。