pre term lablr question

anna

so around 15 weeks i have major bleeding , like a heavy period that lasted 5 hours and than once again 3 days later that lasted 2 hours.... drs were not able to tell me why, but baby was fine. so now i am 28 weeks, do you think I should be worried about preterm labor based on the bleeding I had in early pregnancy? ill of course ask my Ob at next apt, but until than some advise from you ladies?