The 32-year-old model, who is already a mother-of-three, even decided to have IVF treatment after failing to fall pregnant with her cage-fighter beau.
Katie makes the revelation in her new autobiography You Only Live Once, serialised in the Daily Mirror.
She writes: 'After marrying Alex I had only one thing on my mind - having another baby. I'd love to have another four, in fact.
'But by April 2010, after we had been trying for eight months, I became so worried we made an appointment with a fertility doctor.'
It was then that Katie started to accept something may be wrong, and decided to speak to the specialist about undergoing ICSI (Intra-cytoplasmic Sperm Injection).
Despite being needle-phobic, Katie gritted her teeth and underwent a series of painful injections in a bid to fall pregnant.
The process involves stimulating egg production. A sperm sample is selected and injected into the egg before the embryo is put back into the uterus when it starts to grow.
While the process has a 65 per cent success rate, Katie and Alex's first attempt proved disappointing for the pair, and they were told just nine of their eggs had taken - the usual number for a successful attempt is 12 or 13.
However, on the second attempt, Katie felt the process had been more successful, and quickly convinced herself she was expecting.
For complete story, go to: DailyMail
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