The broadcasting legend said she was having a conversation with her boss on the daytime TV show before it went off air for the summer in 2001. She explained that her baby was due in September, the same month the show was due to start up again.
Britton told Kate Thornton on the White Wine Question Time podcast that her boss said: "Well, you've got to come back," and that she told him: "I'm 44. I can't just turn up."
Britton continued: "And he said: 'Well, if you don't come, then there's no job for you.' I went: 'Sorry, then that's bad timing. But no, I can't I can't just turn up at work having just had another baby. No.'
WATCH: Fern Britton on taking her newborn daughter to work with her on 'This Morning'
"Anyway, after a few months, there was a bit of a disaster going on at This Morning, they didn't have the right presenters. And then I was telephoned."
This Morning came under fire for bringing in Coleen Nolan and Twiggy for a brief presenting spell on the show but a dip in ratings saw Twiggy dropped, and bosses back on the phone to Britton.
She said: "I don't think they had a very happy time." She explained that when John Leslie was brought in he called her because they had worked together before but she said she didn't think she could do it.
Then TV bosses tried again, and this time they were able to meet her demands regarding baby Winnie, Britton's daughter with chef Phil Vickery.
Britton told her boss: "I'm gonna have to come with Winnie everyday because I'm feeding her, and she can't be without me.
"Can you help me [with] somebody to look after while we're on air? So they said: 'Yes, that's fine.' So then I did that for a year and it was fun, because she had her picture taken with so many people in the green room.
"And she would sleep and eat and I'd feed her in commercial breaks. And on talkback, sometimes I'd hear, during an important interview, they'd go have 'Fern, just nod. Is the Calpol in the bag? Is the Calpol in the bag?'"
Thornton asked what it took for the attitudes on the show to change like that. She said: "Look at how the how the attitude changed when they needed you to do it. 'How can we help? Do you want a nanny? We'll ask questions about Calpol on talkback!' I mean, why could they not have just done that in the first place?"
Britton, who has three other children with her first husband TV executive Clive Jones, said she had to explain to one boss the difference between her coming back after a caesarean section at 44 and his 30-year-old wife who had been 'driving after two or three weeks', saying all situations are different.
She told Thornton she thought they didn't offer to help in the first place "because the programme bosses were men. I'm not a man hater, but I am a feminist. People seem to equate feminism with man hating. It's not that as we know, it's not."
The presenter, who is also a bestselling novelist, said she thought things might be a bit different now, but also that she had never been one to make things difficult at work.
She said: "It's 20 years ago for a start, so it was a long time ago. When things hadn't moved as fast as they have now.
"And I accepted it because, in general, I don't think I've ever been a pain in the a**e to work with. I just kind of go okay, whatever!"
Yahoo has contacted the This Morning for a response.
WATCH: Fern Britton on family secrets, her struggles with IVF and where she keeps her NTA