One of the most common abnormal Pap smear causes is the presence of human papillomavirus (HPV). According to the Centers for Disease Control and Prevention, HPV is one of the most common sexually transmitted diseases (STDs). It can affect both women and men, and generally it doesn't show any signs or symptoms.

Can chlamydia cause a abnormal Pap smear?

No. A chlamydia infection from years ago would not cause an abnormal Pap test now. Most often an abnormal Pap test is caused from HPV (human papillomavirus infection) which is a sexually transmitted infection.

Can vaginal infection cause abnormal Pap smear?

You have a yeast or bacterial infection

Inflammation caused by a yeast or bacterial infection can throw off a Pap smear result. Usually, either of these conditions would cause itching, burning, abnormal discharge, etc. However, low-grade versions may not be as noticeable.