I'll second the Itti's I have used them on my DD2 since she was about 1 month old and they are great. Just make sure you get the sewn in ones for a little bub, the fit is better than the snap ins when they are tiny. Mine didn't fit her round the legs without gaping though until she was about 5kg, but if you have a chubby thighed bub you should be right to use them earlier LOL

You might find too though that a fitted and a cover is better to contain newborn poos although I haven't used prefolds at all, they just aren't for me. A cover with gussets like Motherease or Thirsties works well as a second line of defense so to speak LOL

All the best with your bub