The 34-year-old former Emmerdale actress said that she had to turn down an opportunity to return to the soap to film her on-screen half sister's departing scenes, as she has been advised to take it easy during her pregnancy.
Until now, Adele has kept her miscarriages a secret and she said the revelation would come as a surprise to many of her friends, but she wanted to share her story to support other women who have experienced multiple miscarriages.
"Some of my friends will be shocked to learn about my previous pregnancies and miscarriages, as I kept them to myself," Adele told HELLO! magazine.
But I want other women to know there's light at the end of the tunnel. Every day now I just think: 'Wow'.
The baby will be Adele's first child with her businessman fiance Oliver Farber.
"I want this to be a success story," she said.
"It sounds awful but I wasn't remotely excited before my five months scan. I didn't want to think about it just in case it was bad news. Now I'm excited but I always touch wood. I know I'm extremely lucky to get this far."
Adele first appeared in Emmerdale in 1993. Her character Kelly was the daughter of Vic and Anne Windsor.
She first left the soap in 2005, but returned for brief stints in 2007 and 2011, and the show's scriptwriters had left it open for her to return again this year to film her half sister Donna's final scenes.
Donna (played by Verity Rushworth) had terminal cancer but died in a shocking twist which saw her throw herself off the side of a building while handcuffed to a criminal.
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