She also wrote that labour "really hurt", but it was OK because was "really cute".
The breakfast TV star and her husband Neil Varcoe welcomed Molly into the world on Wednesday night after a lengthy labour.
The new mum first announced her pregnancy on air back in June.
“The girls already know but Kochie, surprise, we’re having a baby,” she said.
Edwina and Neil wed in April 2018 and were at odds on whether to learn the baby's gender, eventually opting to keep it a secret.
Molly is the couple's first child.
Edwina made her pregnancy announcement live on air in June.
"I have a bit of an announcement myself!" a beaming Edwina told her delighted co-hosts on-air at the time.
"The girls already know, but Kochie surprise..." and before she even gets the words out Kochie screams and goes in for a big hug.
Through all the happy squeals of delight from Kochie, Edwina says: "We're having a baby!"