How early can an ultrasound show ectopic pregnancy?

Ectopic pregnancies can sometimes be seen on ultrasound as early as 4.5 weeks of gestation, but they are not always visible until closer to 6 weeks. This depends on the location of the pregnancy and the sensitivity of the ultrasound equipment. If an ectopic pregnancy is suspected based on symptoms or blood tests, repeat ultrasounds may be necessary to confirm the diagnosis and monitor its progress.