Brief Answer:
CAN BE OVULATORY SPOTTING, BETTER TO CONSULT
Detailed Answer:
Hello
Thanks for writing to us with your health concern.
The days correspond with her probable days of ovulation, if she has been having regular cycles.
SO it could be mid cycle ovulatory spotting.
Spotting after sex can be due to a
cervical polyp, erosion or growth on the
cervix.
However, since this has not happened before, and is only the first time, I do not think this is the reason.
Rarely, spotting after a period can indicate a
miscarriage or an ectopic
pregnancy.
What you can do is continue having sex, and trying for a baby.
Meanwhile, you should also consult a gynecologist.
She should undergo an internal check up - per speculum and per vaginum.
Also, a pelvic
ultrasound scan done transvaginally.
This will tell you if she is ovulating, or some other pathology is present.
All the best.
Please feel free to ask further follow up questions.
Take care.