There are several reasons for finding blood coming from the vagina after making love

You just finished making love and you discover that you are bleeding from your vagina. Bleeding after making love, bleeding after coitus is called: 'Post Coital Bleeding".
Post coital bleeding can happen when you are pregnant and when you are not pregnant. If the bleeding is not severe it's usually not an emergency. While more often than not it's not a serious condition, it's usually best to let your doctor know about it and discuss what you can do to find out the possible reason.
Below are the top resaons for bleeding after sex:

1. Infection of the cervix (cervicitis)
2. Infection of the vagina (vaginitis)
3. Abnormal cervical cells
4. Fibroids
5. Trauma of the vagina
6. Trauma of the cervix
7. Cervical polyp
8. Uterine polyp
9. Threatened miscarriage (if you are pregnant)
10. Ectopic pregnancy (if you are pregnant)
11. Penis trauma (from him)
12. Blood in semen (from him)