I never passed any clots that big and didn't notice them having any effect on my bleeding. I did however bleed for about 5 weeks. If I remember correctly, aren't the discharge instructions that you have to go see dr for any blood clots bigger than a dime? I wouldn't freak out just yet, but if you pass clots larger than a dime, I'd let the dr know. Sometimes, a piece of the placenta can be left behind and you don't want to ignore warning signs.