 We will observe the patency and size of foramen ovale five times within the first 36 hours of life. We will also describe the anatomy of the foramen ovale and the septum primum during this time. The direction of flow across the foramen ovale will also be observed. Other cardiac lesions will be checked for as well. We will measure the change in size of the pulmonary arteries and the closure of the ductus arteriosus. 