This is a very common concern. Many people find that as their baby approaches 6 months old they have to switch to the largest rise setting of one size nappies and also may be fastening them on the bigger waist settings. They wonder how on earth the same nappies are going to last until potty training!
You don’t need to worry too much. At 6 months (or 7, 8, 9 months+ depending on the baby) your baby probably isn’t moving around too much. He/she may be rolling and starting to crawl but is nowhere near as active as an older baby. A little while after your baby starts getting really mobile, you will probably notice his/her shape start to change. Some babies simply stop getting bigger around the waist and bottom but many actually seem to shrink a bit (or tone up!). Your baby’s muscles will become stronger and bigger, but chubby areas like the tummy and bottom will become less squishy. This means that many people will fasten the waist of nappies on the same setting for a long time. My youngest, for example, has had her nappies fastened in the same way since around 8 months old and she is 23 months old now! We even had a brief stint, just after she started running around properly, where I could fasten the waist on a tighter setting. Some people can also go back down a rise setting, presumably because their baby’s bottom is taking up less room in the nappy!
There are, of course, some babies who do grow out of one size nappies before potty training, whether they are out of nappies a bit later than average or whether they’re just a big baby. There are plenty of nappies out there that will accommodate the bigger toddler. A list of suggestions will follow shortly.