Thanks for the follow-up.
That your partner's cervix remains normal in appearance is further evidence that no STD is responsible for the bleeding. Her doctor's advice sounds reasonable to me, but I'm not a gynecologist and have no further opinion about the cause of the bleeding.
OK so a quick update. She just went back to her doctor to explain that the bleeding had continued. Her doc did another examination, and said her cervix looked healthy and the right color (pink, i guess, instead of red?). Because her cervix looked fine, her doctor said that pretty much meant it's not anything serious.
She has an appointment for an ultrasound, but the doctor said it could possibly/probably be a polyp.
I'm just curious if this sounds reasonable to you?
Welcome to the forum. I'll try to help.
The only STDs likely to cause vaginal bleeding after sex are gonorrhea and chlamydia. Either of them can cause cervicitis -- i.e. inflammation of the cervix -- when can bleed as a result being bumped by the penis during intercourse. However, cervicitis that results in bleeding would have been obvious to your partner's gynecologist. Further, the lab tests for gonorrhea and chlamydia, which undoubtedly were done, are very accurate; with the negative results, you can scratch them off the list. (If you would like to be super safe along these lines, you could visit your doctor or a local STD clinic and have urine gonorrhea & chlamydia tests, but I would be very surprised if either were positive.)
In theory, cervical cancer -- which is an STD, in the sense it is caused by certain types of sexually transmitted human papillomavirus (HPV) -- could cause post-sex bleeding, but that too would have been obvious on examination, as well as the pap smear. (And her doctor is correct that neither recent sex nor bleeding has any effect on the reliability of pap smear results. That's an urban myth, which may have arisen in part because many women prefer not to have pelvic exams during their menstrual periods. Anyway, cancer at a stage that would cause bleeding would be visually obvious and would not require a pap smear to diagnose.)
I would tend to agree that trauma during sex seems unlikely; it's hard for me to imagine a cut or abrasion (either of the external genitals or inside) that could explain bleeding and yet not be obvious to the woman herself or her doctor.
Beyond those thoughts, I really can't help. For the reasons above, I imagine the bleeding is caused by an as yet undiagnosed hormonal or other gynecologic problem, not an STD or any other infection. But this is strictly an STD forum, and neither Dr. Hook nor I is a gynecologist and I cannot speculate further. Sorry.
I'll be interested in hearing how it all turns out, if and when your partner has a diagnosis that explains the bleeding.
Regards-- HHH, MD