I am confused here. A hematoma is a collection of blood contained IN the tissues. Not bleeding and clots pouring out of you! Usually bleeding and clots that heavy IS fromt the uterus itself. Constant streaming of blood can be from the uterus or a vaginal or cervical tear (but not usually big and numerous clots that I have seen).
What makes a hematoma so nasty if the blood is trapped in the tissue and causes exteme pain and pressure. I have seen them several times. I have seen them from unmedicated, intervention free deliveries that were 'fast and furious'..where the baby explosively came through the birth canal. But I saw one just resently that was AWEFUL (the worst I had ever seen) from a vacuum delivery. We will never know of course if it would have happened anyway, but the OB used a Kiwi vacuum for really no reason that I could see (besides his impatience). As soon as the baby popped out, the poor ladies right labia absolutely swelled so fast it looked like a balloon being filled at a helium station! And I am not exagerating! I have never, ever seen anything like it! We immediately applied ice and pressure..and I had to put a foley catheter in her asap so urine could actually drain from this lady. The hematoma was SOOOO big, that it pushed her opposite labia majora over. There was now way that woman would be able to pee on her own until some of the swelling went down.
I thought for sure we would take her to the OR and drain it, but the OB said that it is so difficult to actully find and cauterize the bleeding vessel, that it is better to leave the hematoma alone if it is not enlarging, and the back pressure would actually staunch the bleeding.
The swelling was a million times better in 2 days (which surprised me), but she came back into the hospital 4 or 5 days after discharge begging for it to be operated on. They refused since it really did look excellent and she was having no difficulty peeing or getting around.
I don't know what the point of my rambling was! In answer to your question, the hematomas I have seen have been random, and SOME related to quick pushing, and instrumental deliveries. I would suppose that if you had some funky vessel(s) in your vagina, that were say 'weaker' than you could be at higher risk for this happening..but I don't even know if that is a medical condition or I am just rationalizing! LOL!
I have not personally seen anyone have it happen twice to them.