OMAHA, Neb. -- Four tiny babies are being cared for at the Nebraska Medical Center.

The quadruplets were born last month to Lee and Rachel Woolen, of Holdrege, Neb.

The three boys and a girl each weighed about 1.5 pounds.

NMC said the babies remain in extremely critical condition. Doctors said they are optimistic, and that the quads are doing very well, considering their size.

The babies could be in the hospital's neo-natal intensive care unit for another three to four months.