Talking to the Daily Mail, the 35-year-old recounted the heartbreaking story.
'It's your worst nightmare. All your hopes and dreams you had for this little person just comes crashing down.'
The former reality star recalled to the publication how she noticed her bump wasn't 'getting any bigger' at 30 weeks, but her doctor 'assured [she] was a good size.'
However, at 37 weeks Bree's midwife was unable to locate a heartbeat.
Bree, who shot to fame on Big Brother in 2004, had developed some blood clots on her placenta which prevented the right nutrients from getting to the foetus.
'The hardest part to deal with was knowing Archie's death was completely preventable,' she told the publication. 'I had all the warning sings but they were all ignored.'
Bree and Evan are now parents to nine-month-old Hunter Wilkes.
This article originally appeared on New Idea.