The 33-year-old is one of the last remaining original actors on the BBC period drama, and as the years have gone on, creator Heidi Thomas has worked alongside the writers to develop Trixie’s character.
But while the midwife has suffered through alcoholism and the harrowing nature of the profession at Nonnatus house, she has come out relatively unscathed.
Now Helen has revealed that Trixie’s past is about to come back to haunt her.
Speaking to TV Times magazine, she shared: “Her work is a worry because with such a stressful job, it will become a tricky thing for her to keep spinning all of the plates. It’s a problem that’s easier for Trixie not to face up to…”
Season seven of the series has seen the complex character falling even more for dentist Christopher (Jack Hawkins), but it won’t be plain sailing for the pair.
“Although she loves him, she is still vulnerable,” Helen continued. “This week, Trixie learns that his daughter Alexandra is being affected by his divorce from her mother.
“She’s tried hard with Alexandra, but a case that Trixie deals with makes her realise what a huge effect a broken home can have on a child.”
The star went on to say that the reason she’s kept coming back to Call the Midwife lies within her character’s journey.
She explained: “I’m so lucky to have been able to grow the character over a long period.
“She could have carried on as the blonde talking about boys and having a fag, but the writers have peeled back layers to show her darker side, which has been exciting for me.”
The actress recently gave birth to her newborn baby Wren Ivy with co-star Jack Ashton, which led to her taking time out from the latest series on maternity leave.
Hinting at how Trixie’s departure would come about, Helen revealed: “It becomes a natural conclusion for all in Nonnatus House, and Trixie, that it’s only right for her to take time out.