The Celebrity Big Brother star, who is pregnant with Alex Reid's baby, began suffering from heart palpitations two weeks ago, resulting in her feeling dizzy and faint and struggling to breathe.
She was rushed to the Lister Hospital in Chelsea last Wednesday (March 14) for tests due to her abnormally high heart rate. Houghton later collapsed while shopping on Oxford Street on Friday (March 16).
"I worry that something will happen to me, that the baby will be born and I won't be here. The doctors said that when you're in labour your heart goes up even more and so I'm terrified of the whole thing," she told The People.
"I also worry that I will go into labour early and then who knows what will happen. I want to have a natural birth, I don't want a Caesarean, but there is such a big fear that something could go wrong. I just want to hold my little girl and meet her.
"I have a family history of heart problems so I have to be so careful. I am having to stay as calm as possible, then there is less chance of my heart rate... go[ing] through the roof so often. I'm so worried for my little girl. I fear so much for what is going on in her little body.
"My fertility problems meant that I didn't think I could ever be a mum so I pray that she's going to be safe. Her heartbeat replicates mine and sometimes I think I'm going to die. She's my little miracle so she has got to be okay. I just feel so bad for what is happening."
Speaking of claims that Reid has been messaging Amy Willerton, the 19-year-old who won ex-wife Katie Price's modelling competition, behind her back, Houghton admitted that the cage fighter has lost some of her trust but insisted that they are focusing on the baby rather than arguing.