Wool diaper covers prevent nighttime leaks
More soft, wooly advice from Tiffany:
Another nighttime leaky diaper tip: Diapers do not fit all kids all the time, add the nighttime shuffling and leg bending and, well... even the best fitting diapers can leak. A wool diaper cover (sometimes called a soaker) could be the answer! Imagine a soft sweater combined with a pull-up, the waist and legs ribbed to fit close. Plus, wool is breathable and anti-bacterial. If you're handy with the knitting needles, you could check out this free pattern. Otherwise, Aristocrat makes a great one.
Related: Wool blanket as mattress protector