Hi, and thanks for your medical question on eHealth forum!
Any spotting or bleeding in first trimester should never be ignored. It can be due to simple causes such as cervicitis (infection/inflammation of cervix), vaginitis (infection/inflammation of vagina), or it can also be due to a part of uterine lining sloughing or due to threatened abortion. Sometimes it happens without a cause.
Since a confirmed diagnosis cannot be given on net please discuss these possibilities with your gynecologist once. Hope this helps. Take care!