Brief Answer:
NEEDS WORKUP, MORE DETAILS NEEDED TOO.

Detailed Answer:
Hello
Thanks for writing to us with your health concern.
Have you ever had such an episode in the past, was this your first time having sex ?
How much of bleeding was there, or was it more of spotting ?
As such, it is not necessary that bleeding after sex indicates STD.
SOmetimes, rough sex can lead to abrasions or tears that cause bleeding.
When was your last period - if it was just over or about to come, mild spotting might ensue as sex stimulates uterine contractions.
Other causes include - polyps, foreign bodies, cervicitis or a growth or lesion on the cervix.
If you are nowhere near your period , and have had no rough sex, you need to have an evaluation.
This would include an internal exam by a gynaecologist - a per vaginum and per speculum check up.
Also a Pap smear and a pelvic ultrasound scan.
All the best
Please feel free to discuss further.

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