The 36-year-old former Spice Girl - who already has daughters Phoenix, 13, Angel, five and eight-month-old Madison - admits that next time around she would like to have a son.
She said: "I do want a boy. But I`m enjoying my girls and my baby.
"It would be nice to have a son, but it wouldn`t be straightaway. The gap between Madison and Angel works brilliantly. I`ve just had them all on Skype and Phoenix is holding Madison and Angel`s playing with Phoenix`s hair. It`s beautiful."
The `Wannabe` hitmaker - who lives in Sydney with husband Stephen Belafonte - has lost 33lbs since giving birth to Madison and admits she finds it hard to keep her weight in check when she`s expecting.
She told the Daily Mirror newspaper: "I`m not the best example of what to do in pregnancy - I always put on too much weight. And I put on a lot this time. A lot.
"I enjoyed myself. And just ate everything. It`s not like I had a particular weakness or craving. If I wanted pizza I had it. I also didn`t exercise because I was so sick. But at 36 years old, it takes more effort to get the weight back off. It`s not like 13 years ago when I could pop a baby out and just snap back into shape."
She now wants to ensure her girls develop healthy relationships with food by teaching them how to eat well.
She explained: I tell them you don`t have to be a certain size, but you do have to treat your body a certain way. "Phoenix is into sports but she likes junk food, so I tell her it`s a treat for weekends. But you have to set an example - she sees me packing a healthy lunch for work. We`re all in it together. My husband`s on a healthy eating plan, too."