Chances are she was in labour. When I went into labour and lost my mucus plug a lot of blood came out that had just been sitting in the bottom of my uterus not hurting anything. It should also be noted that it could be normal for a woman to lose around 500ml of blood during delivery (pregnant women can have as much as 40% more blood volume than a normal woman). Chances are baby and mom are doing just fine. *Note from the hubby: he's going to give a slightly modified version of this scenario to his EMT students to see how they do. A big thank you to Mr. Reynolds for the inspiration.