S.,
I would talk to your doctor about having blood work done to specifically check for a possible bleeding disorder. There is actually a disorder out there called Von Willdebrand Disorder, where it is not caught until major surgery or delivery. You could possibly have a very mild case, and may be why you did not have the problem with the first one. This can be for both boys and girls, but generally this particular bleeding disorder is found in women and heavy/irregular periods. Most doctors miss it, and state, simply that a person has Menorrhea (heavy bleeding)and really don't know what to do about. Due to missed diagnoses, most women end up having to go through drastic measures to stop the bleeding.
It's just a suggestion to bring up. They can do blood work to test for the Von Wildebrand's factor level. Might be worth bringing up, because it is so treatable. If you do have it, they would give you the missing Von Wildebrand factor as a shot which would be like having blood work done or IV put in temporarily, but after they get the level up, you are generally better, until you have another major incident.
Of course, I'm no doctor, but do know I went through close to 18-20 years of the doctor's not knowing why I would have heavy bleeding and missed periods, then have one for 6 weeks, then stop one week and start over. I personally don't have Von Wildebrand disorder, but they were able to diagnose my problem after we had my son.
Hope it helps,
T.