Does Bleeding During Pregnancy Indicates Miscarriage?

hi there my girlfriend is 18 years old and i am 19 years old she has had 2 miscarriages first one was when she was 17years old that was in november 2009she started bleeding lost the baby at 6weeks, the 2nd was in may 2010 we went for a scan as she was bleeding again but there was no heart beat so she ended up going to the hospital the next day to go in for the vacuasion the baby was 8 weeks and now she is pregnant and is 9weeks but bleeding again she has had to blood test first was a high one but the second was lower by a 1000 is this leading to another miscarriage ?