Inserts absorb and hold the waste when a diaper is soiled. Usually they are sewn to the inner layer of a cloth diaper, laid into the diaper, or stuffed into an opening inside the diaper. Disadvantages of an insert permanently sewn to the inner layer that is one size include that when on a baby the size and amount of waste changes as they grow. This presents issues including the diaper insert being too bulky which can make movement difficult for a small baby that does not really need all the extra absorbency capability of the bigger insert to even a leaky insert that cannot hold enough waste of a larger baby with increased absorbency needs. The sewn-in insert takes on a one size fits all approach but a growing baby and even different babies have more individualized needs at various times of growth where this one size approach is not accommodating.
Another disadvantage of inserts currently on the market is that the inserts can become rather bulky especially as the baby grows bigger in size due to the fact that bulky materials can be used and or the materials have a low absorbency in relation to the thickness of the materials used.
Another disadvantage to inserts stuffed into a pocket opening type reusable diaper, for example, is that it can be difficult to guide the insert, get it to lay flat inside the pocket, or get it to lay in the right spot especially if more than one insert is needed to absorb the wastes.
Reusable diapers on the market cannot be held shut in any manner to contain wastes. This can especially be a nuisance when more than one insert is needed to hold the waste, a large amount of stool is present, or when you are not at home but at a store shopping, for example. Diapers can be rolled up if the inserts are not too bulky. However, the diapers can easily fall open. This can be difficult when on the go and out and about or with a messy stool. Other disadvantages of diapers that cannot be closed up until they are ready to be cleaned include sanitary and risk of possible contamination of wastes with other objects that could potentially come in contact with a diaper that easily falls open. Cleanliness and sanitation become an issue when using reusable cloth diapers.