This is an ultrasound examination that is usually done vaginally in the 6th to 10th week of pregnancy. The purpose of this test is to determine the number of embryos (if it is multiple pregnancy, chorionicity) and whether pregnancy normally develops within the uterus.

This imaging test is useful for women who experience low abdominal pain or bleeding during pregnancy and those who have a history of reccurent miscarriages or ectopic pregnancy.