A Florida woman who delivered a 14.1-pound (6.4-kilogram) baby says she didn't know she was pregnant until her third trimester.

Officials at St. Joseph's Women's Hospital in Tampa say Maxxzandra Ford delivered her son, Avery, on Jan. 29. They say the infant is the heaviest born at the hospital, and one of the largest-ever born in the state.

Ford tells television stations WFLA and WFTS she had been rapidly gaining weight last fall. Eventually, doctors confirmed she was 35 weeks into her pregnancy. Ford said she initially thought she was having twins.

After 18 hours of labour, Ford naturally delivered Avery, who remains in neonatal intensive care but is expected to go home soon.

Ford, who also has a 1-year-old son and 5-year-old daughter, says she "just melted" when she finally held Avery.