Doctors at Abington Memorial Hospital delivered the Montgomery County hospital's first set of sextuplets Wednesday.
The three boys and three girls were premature and are in the hospital's neonatal intensive care unit, spokeswoman Linda Millevoi said.
She said she could say only that the family is "local." She could not say why or how the babies were delivered early, how far along in pregnancy the mother was, whether the mother had had fertility treatments, or how old the mother is.
No pictures were released. The hospital said more information would be released "in the near future and at the family's discretion."
Of the 4.2 million births in the United States in 2008, only 46 were quintuplets or larger groups of multiples, according to the U.S. Department of Health and Human Services. Contrast that with the nearly 139,000 twins and about 5,900 triplets born that year.