“…Smithson et al 1 have highlighted that first trimester discordancy for fetal size may occur in monochorionic twin pregnancies. In all such cases, in addition to fetal crown -rump length, it is important to assess other parameters which may reflect the underlying placental vascular pattern, such as fetal nuchal translucency measurements and Doppler velocimetry of the ductus venosus 5 , in order that the most accurate assessment of risk for development of subsequent severe twin-to-twin transfusion syndrome can be provided, and hence, appropriate antenatal surveillance can be planned.…”