After delivery it will take around two months for the genital organs to come back to normal stage.
And during this time the increased vascularity to the genital organs can persist.
So that may be one possible cause for your problem.
And also during early postpartum months due to hormonal
imbalance intermenstrual spotting can be seen.
One more possibility is post coital tear.
So you once consult gynecologist and get examined.
If no local cause is found, anti-fibrinolytic drugs can control the bleeding.
If the spotting repeats, with your doctor's advice you can go for progesterone
That will help in decreasing spotting and also for contraceptive