I understand your concern.
In my opinion there can be different causes for spotting or bleeding during pregnancy
1)Hormonal insufficiency like progesterone
insufficiency,thyroid abnormalities etc.
2)Abnormal pregnancy like miscarriage
3)Bleeding from cervix .
4)Bleeding due to excess physical strain.
So once there is spotting or brown discharge all the above causes should be ruled out.
I suggest you to consult doctor
for physical examination and and necessary investigations.
The investigations like thyroid profile,ultrasound might be needed.
Physical examination helps to rule out any bleeding from cervix.
Nothing to worry.It will subside once the cause is treated.
Avoid physical stress and intercourse.
Hope this helps.