"Like so many Americans, the president and first lady and the entire first family, you know, are -- wait with anticipation for the birth of the duke and duchess' child," spokesman Jay Carney told reporters.
The Obamas "wish the family and all of Great Britain well on this pending momentous occasion," Carney said.
The Duchess of Cambridge was admitted to hospital early today, but there was still no news for the hundreds of international media camped outside.