The Girls Aloud star - who is married to soccer star Ashley Cole - is worried she may never become a mother if she doesn't have a baby soon.
She said: "Having a baby is important to me because I am from a big family. I have friends who have put it off and I don't want to do that. I feel like all this that I do is just make-believe and at the end of the make-believe I will always have my family. So if I am blessed, I would love a big family. But nobody knows, do they?"
The 26-year-old singer - who has four siblings - added she hasn't started trying for a baby yet, but will do so before long.
She said: "Preferably sooner rather than later. I'm not pregnant now. The chance would be a fine thing - I haven't been home!
"It would never be perfect timing, so I am not trying, I am preventing."
