After her release earlier this month, hospital officials said she weighed 2.5kg. Picture: YouTube.com

Little Baby Saybie was born at 23 weeks at a San Diego hospital in December last year - making her the world's smallest surviving baby.

Now five months old, she has finally been discharged. When Saybie was delivered via C-section, she weighed just 243 grams - about the weight of a large apple, according to CNN. After her release earlier this month, hospital officials said she weighed 2.5kg. 

"After experiencing severe pregnancy complications, Saybie's mother gave birth via emergency cesarean section at 23 weeks, 3 days gestation in the womb," the hospital said during a news conference. 

"Doctors said the preterm birth was necessary after they found that the baby was not gaining weight and her mother's life was at immediate risk."

Saybie's family have given permission to share her story, but chose to remain anonymous. According to the Tiniest Baby registry maintained by the University of Iowa, she is ranked as the world’s smallest baby ever to survive.