Embryonic pole (fetal pole)

The embryonic pole, also called the fetal pole, is the earliest visible part of the developing embryo on ultrasound, usually seen from around five and a half to six weeks of gestation. Its length can be measured (crown-rump length) to help confirm dating. Once an embryonic pole is visible, the sonographer will look for cardiac activity at the same or a following scan. If a gestational sac has grown to a certain size without a visible embryonic pole, your clinic may recommend a repeat scan after a short interval before drawing any conclusions, since normal development varies by a few days from person to person.

Also known as: fetal pole, foetal pole

Last reviewed: 9 September 2026. Written by the Antega Editorial Team. General information only — always follow the advice of your own clinic, doctor or pharmacist.