Rate and amount of menstrual bleeding is different for each individual. The amount does not change day to night. Your period doesn’t care if you’re sleeping or not, and flow continues. The difficulty with night time is that we are not as aware of what is going on. We sleep for six to eight hours or more, and are much less likely to get up and check flow status then we are during the day. If you are bleeding through on a regular basis, be sure to get up once at night and change your pad and tampon.
I also want to point out the role gravity plays at night. While on your period you experience small uterine contractions that help expel blood and tissue from your uterus. During the day while standing or sitting, the menstrual flow easily falls straight downward (this is the gravity part) onto your pad or tampon. Now at night, this process continues while you are sleeping and laying flat. As the blood comes out, instead of going directly on the pad like when we are standing up (simply flowing directly downward), it seems to go everywhere and anywhere else. Don’t we all have “period underwear”? Stains on the back of our underwear, straight through to the bed sheets and sometimes even on the comforter. Ugh! Sleep on your side and the bleeding tends to fall towards the inside of your leg closest to the bed, pajamas, sheets and comforter. Frustrating. Be sure to wear the pad and/or tampon with the right amount of absorbency. Wear firm-fitting underwear to hold the pad close against your body. It is fine to wear tampons at night, though you should change after 6-8 hours. If your period is excessively heavy, where you need to change your pad or tampon every two hours or more, or you are passing clots bigger than a quarter, you should contact your healthcare provider.
When it comes to periods, there really is no “should be” — we're all different. I have two or three really heavy days (and nights) when I'm menstruating, too. I think your tampon plus an overnight pad is a good plan, but if you're soaking through you may need to set your alarm for a middle-of-the-night change. I know, I know... that's about as fun as a math test, but it's a heck of a lot easier than having to wash your sheets every day of your period. If your period is this heavy every day and/or it's lasting longer than seven days, be sure to tell a trusted adult about it. If that's the case, it may not be a bad idea to make an appointment with your healthcare provider.
Every woman’s flow is different and can change not only with each period but her throughout her lifetime. For the first few years of my period my flow was really heavy. As I’ve gotten older it has slowed a bit. But even at its heaviest, I don’t remember ever soaking through a tampon and a super pad. I think it would be good idea to see what our Health Expert Michelle has to say about this.