China Baby Diaper Machine company give several reasons why a baby’s diaper may leak at night:

Over-saturation

If a baby’s diaper is not absorbent enough, it may become over-saturated and leak. This can happen if the diaper is too small or if the baby is a heavy wetter.

Incorrect size

If the diaper is too small or too large, it may not fit properly and may not be able to contain urine. Make sure to choose the right size diaper for your baby’s weight and adjust the fit as needed.

Improper fastening

If the diaper is not fastened properly, urine may leak out of the leg openings or waistband. Make sure the diaper is snug but not too tight, and check that the leg cuffs are fitted properly.

Diaper type

Some diaper types may be more prone to leaking than others. For example, diapers with less absorbent materials or those with a less secure closure system may be more likely to leak.

Sleeping position

If your baby sleeps on their side or stomach, urine may pool in one area of the diaper and cause leaks. Try changing your baby’s position or adjusting the diaper to prevent pooling.

Timing of diaper changes

If your baby’s diaper is not changed frequently enough, it may become over-saturated and leak. Make sure to change your baby’s diaper regularly, especially before bedtime.

To prevent diaper leaks at night, it’s important to choose the right size and type of diaper for your baby, ensure a proper fit, and change the diaper frequently enough to prevent over-saturation.