CRL: Crown—rump length; EV: Embryo volume; FV: Fetal volume; GSV: Gestational sac volume; PV: Placental volume; SonoAVC: Sonography-based automated volume count ...

The frequency dependence of attenuation of broadband ultrasound and the velocity of ... study was to see how BUAC and velocity change with gestational age (GA) and postnatal age (PNA).

Gracia and Barnhart [6] compared different methods of diagnosing ectopic pregnancy using combinations of transvaginal ultrasound ... which can mimic a gestational sac giving a false picture ...

Mild cramps in the lower abdomen, similar to menstrual cramps. "An ultrasound scan may also reveal an empty gestational sac with no visible embryo or heartbeat. This is often the definitive sign ...

During the first trimester of pregnancy, healthcare providers typically perform a transvaginal ultrasound to determine the ...