A new mum was so dosed up on painkillers, she forgot she gave birth.

Look, forgetting your kids’ birthday happens — but forgetting the trauma of the day you gave birth? Never.

Unless you’re very, very lucky, or Tisha Heffron, a Californian mum who is both. She’s also hilarious.

Heffron, was so chock-full of morphine after the labour of her second born, she completely wiped it from her memory.

She and her husband James welcomed baby Clay at a Californian military hospital on February 6.

Tisha and James. Source: Facebook

"I've been sleeping all this time," she tells her husband, who politely disagrees while filming the whole exchange.

When he tells her she just gave birth, she asks, "To who?"

And the questions keep coming:

"When? This morning? Oh. Are you my brother?"

Mamamia Out Loud: Would you snapchat your birth? Post continues after audio.

Eventually Tisha remembers, but not before declaring the child came out of her bully button, unleashing a whole lot of swears and asking if there are bugs on her face.

“I was torn between trying not to laugh and making sure Tisha didn’t stand up," James told The Sun.

“This went on for at least 10 minutes before she fell asleep again.”

Watch the footage here: