Bianca is on a high following her wedding to Liam Murphy (Axle Whitehead) when she receives the bombshell news.
The Summer Bay blonde has always thought that Liam is the father of her unborn child, but she starts to question herself during a routine ultrasound.
Lisa Gormley, who plays Bianca, told TV Week: "She finds out she's a bit further along than she thought, which would come as a bit of a shock to anyone.
"For the first time, she's questioning who the father could be - and she really needs to check her dates."
Pondering what might happen if Bianca discovers that Heath (Dan Ewing) really is the father, the actress continued: "I think she'd be petrified she'd lose Liam. If that was the case, she'd assume he would walk away from her. There are some really big decisions ahead. It could either tear them apart or bring them together."
Bianca's pregnancy story has already begun on screen in Australia, while fans in the UK will see her tell Liam that she is expecting a baby later this week.
Home and Away airs the ultrasound scenes next week on Network Seven in Australia and next month on Channel 5 in the UK.
> Home and Away's Lisa Gormley chats to Digital Spy
> Read more Home and Away spoilers and news