Teigen wrote on her Instagram post that the road to pregnancy has not been easy for her and Legend but they have kept trying because they can't wait to bring their first child into the world.
She wrote: "We're so excited that it's finally happening.
"Thank you for all your love and well wishes.
"I look forward to all the belly-touching!"
On FABLife, Teigen said that she had been surprised at the "shame" that came with fertility troubles.
"But my gosh, it’s been a process.
“We've seen fertility doctors and once you open up about those things to other people you learn that a lot of other people in your life are seeing these people and they have this shame about it."
Teigen also revealed that she had had lots of trouble coping with people questioning her on when she would start a family.
She won't have to field these questions any more and does not plan to stop at one.
Teigen told People: "I picture us with three or four. John and I go hard in everything we do. And we like a bit of chaos. No nannies, drivers or maids (to look after the kids)."
The supermodel is not alone and other Hollywood celebrities have publicly struggled with pregnancy woes.
1. Nicole Kidman
In 2011. Nicole Kidman spoke to ABC News about her fertility troubles and revealed that her daughter who was born in 2010, was born via a gestational carrier.
Kidman has four kids. Her two children with Tom Cruise were adopted (Isabella and Connor Cruise). In 2006, she married singer Keith Urban and they had a daughter — Sunday Rose Kidman Urban — in 2008. Faith Margaret Kidman Urban was delivered via a surrogate two years later.
2. Courtney Cox
Last year, Courtney Cox revealed that she had multiple miscarriages before she gave birth to her daughter in 2004.
The Friends star, who used to be married to actor David Arquette, told People Magazine said that she had struggled for years to carry a baby to term.
She said: "I get pregnant pretty easily but I have a hard time keeping them."
3. Gwyneth Paltrow
PHOTO: HUGO BOSS
In an interview with Mail Online in 2013, Gwyneth Paltrow talked about the pain she felt suffering a third miscarriage.
The miscarriage had also put her own life at risk.
Paltrow, who has two children with former-husband Chris Martin, said: "My torment at losing my third baby... and nearly dying."
She admitted that she keeps thinking that she has missed the window for becoming a mother again.
Source: People Magazine, CNN, Mirror UK