A vesico vaginal fistula (VVF) is an abnormal connection between the bladder and the vagina, resulting in the continuous and uncontrollable leakage of urine into the vaginal vault. The most common cause in developing countries is prolonged obstructed labor, where the baby's head compresses the mother's soft tissues against her pelvis for an extended period, leading to tissue death and fistula formation. In developed countries, VVF is more often a complication of pelvic surgery, particularly hysterectomy, or a result of radiation therapy for pelvic cancers. Other less common causes include pelvic trauma, infections, or certain cancers. The primary symptom of VVF is the continuous, involuntary leakage of urine from the vagina. This can lead to skin irritation, recurrent urinary tract infections, and significant psychosocial issues including depression, social isolation, and in some cultures, ostracization.

Diagnosing a vesico vaginal fistula typically involves a combination of clinical evaluation and diagnostic tests. The process usually begins with a detailed medical history and physical examination. A pelvic exam may reveal the presence of urine in the vagina or the fistula itself if it's large enough. Dye tests are commonly used, where the bladder is filled with a colored solution (like methylene blue) and a vaginal tampon is inserted; if the tampon becomes stained, it confirms the presence of a fistula. Cystoscopy, where a thin tube with a camera is inserted into the bladder, can help visualize the fistula from the bladder side. Imaging studies such as CT scans or MRIs may be used to precisely locate the fistula and assess its size. In some cases, retrograde pyelography or voiding cystourethrography might be employed to get a clearer picture of the urinary tract anatomy and the fistula's location.