A bicuspid aortic valve is an aortic valve that only has two leaflets, instead of three. The aortic valve allows oxygen-rich blood to flow from the heart to the aorta. It prevents the blood from flowing back from the aorta into the heart. An abnormal aortic valve develops during the early weeks of pregnancy, when the baby's heart develops.
Update Date 5/14/2014
Updated by: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.