Hello dear
Understand your concern.
I think blood is from genital track.
It mainly due to
hymen rupture in first time sex or due to rough sex.
Generally It will disappear its own.
But if it will persist , you should consult the doctor for below other causes:
Following are the other causes of your problem:
1. Cervical dysplasia
2. Vaginal infections:
gonorrhea, chlamydia, yeast, trichomonas
3. Cervical polyp
4. Endometriosis
5. Fibroid
6. Vulvovaginitis
Consult the gynecologist and do the following tests:
Pelvic examination
PAP smear
Endometrial biopsy
Hormonal profile
Urine routine and microscopic examination
Gram stain, culture, PCR and NAAT test for diagnose vaginal infections
Use safer sex technique
Use condoms and lubricants during sex
Maintain hygiene before and after sex/urination
insert the penis in the vagina after it get fully wet.
Hope this may help you.
Best regards
Dr. Sagar