What is fetal cardiac echo?

Cardiac echo is the examination of the fetal heart using ultrasound imaging. This involves different modalities including 2D gray scale, color Doppler, pulsed wave Doppler and M-mode imaging. Fetal echo can detect up to 90% of major cardiac defects if done by an experienced physician. However, there are certain cardiac defects, which cannot be detected prenatally, and therefore a negative test does not preclude entirely the possibility of their existence.