No, there are two reasons for this; 1.Tampons are a risk no matter how long they are used for, however the longer they are used the greater the risk because the more bacteria get to multiply within the vagina. Tampons need to be changed at least every 4-6 hours to limit the growth of bacteria, most people sleep for 8 hours, and most people would be unable to wake themselves up in the middle of the night to change their tampons. Bacterial growth like this is linked to TSS and vaginal infections such as bacterial vaginosis. 2.Tampons absorb vaginal fluids, these fluids normally would clean out harmful bacteria but tampons prevent this, fluids also act as a protective layer coating the vaginal walls. Tampons absorb vaginal fluids so this causes vaginal dryness, in turn this results in vaginal splitting and ulceration – this occurs whenever you use a tampon. When laying down, such as while asleep, menstrual blood does not flow down into the tampon, as a result the tampon will absorb more vaginal fluid which leads to more vaginal damage. This damage is linked to TSS, it’s also thought to be responsible for heavier periods and heavier menstrual pain. Basically you need to use pads at night, not just to avoid the above problems but it also gives your vagina a chance to clean out all the bacteria, harmful chemicals and fibres that tampons introduce into the vagina and prevent it from cleaning out. You can however use other internal options like menstrual cups or softcups at night, because these are much cleaner and safer than tampons it means they can be left for up to 12 hours without health risk or risk of leaking. Menstrual cups and softcups also don’t damage the vagina at all, so they aren’t linked to any of the health problems that tampons are linked to.