Perform comprehensive obstetric ultrasounds including first trimester scans (NT, early anatomy), detailed second- and third-trimester anatomy surveys, growth and biophysical profiles (BPP), multiple gestations, cervical length assessment, placental evaluation/PAS, and Doppler studies (umbilical artery, MCA, ductus venosus). Support fetal therapy and invasive procedures (including amniocentesis, CVS, PUBS/cordocentesis, and selective fetal reduction) performed by physicians - sonographer role is supportive only and does not include guiding or performing these procedures.