With 24 percent of the vote, Holly narrowly beat Girls Aloud star Kimberley Walsh who gained 21 percent of the vote.
Keeping up with the Kardashians star Kourtney took 15 percent of the votes, while Billie Faiers, star of The Only Way Is Essex, took 14 percent.
CLICK ON PHOTO FOR BABY BUMP GALLERY
Holly Willoughby and Kimberley Walsh
Mila Kunis, who is expecting her first child with fiancé Ashton Kutcher, took home nine percent.
Holly, the popular This Morning presenter, revealed her news in March, and told fans that she is bubbling with glee about her bun in the oven. The host is married to Dan Baldwin, a producer she knew from Ministry of Mayhem.
"Surprise Surprise (and it was a surprise!!) I’m really happy and excited to tell you that Dan and I are expecting baby number 3!!" she wrote on her website, OfficialHollyWilloughby.com.
"We feel blessed and very lucky to be giving Belle and Harry a little brother or sister later this year. Xxx"
Holly got married in August 2007 and she shares four-year-old son, Harry, and daughter Belle, almost two, with Dan.
"Holly Willoughby has impeccable taste and style. She always looks classy and fashionable and dresses appropriately for her age and the presenting work she does. She definitely has a pregnancy glow at the moment – she looks terrific", said one voter to website My1stYears.com who carried out the survey.
Another fans said of Kimberley: "Kimberley Walsh looks amazing. Her maternity outfits have been so her – very stylish, figure hugging and not straying too far away from what she normally wears."
Other celebs who gained votes included The Avengers actress Scarlett Johannson, whose pregnancy was unveiled by her producer in March, and model Erin O'Connor.