The 17-year-old's alter ego Lucy Beale will discover that she is pregnant later this year following a number of encounters with Walford newcomer Leon Small (Sam Attwater).
Discussing the surprise twist, Suffield told New: "I'm excited about the storyline because it's something brilliant to get my teeth into. I love playing 'bitch Lucy', but you'll soon see a completely different side to her."
On how Lucy will react to the responsibility of motherhood, she admitted: "I don't know what she'll do. She's good at rising to a challenge. But then she's always out drinking with her mates, so in that respect I think she'll see it as a burden."
Lucy's new storyline is expected to send shockwaves through the Beale family as her stepmother Jane (Laurie Brett) has been desperate to adopt or foster a baby for months.
A source recently said: "Emotions are set to run high for all the Beale family over the next few months and there will be many twists and turns ahead."