Final answer:
Pneumaturia is the finding that would support the proposed diagnosis of a vaginal fistula, as it indicates the presence of air in the urine due to an abnormal connection between the bladder and another organ.
Step-by-step explanation:
The nurse is caring for a woman suspected of having a vaginal fistula. The finding that would support the proposed diagnosis is pneumaturia, which is the presence of air in the urine. Pneumaturia can occur when there is a fistula (an abnormal connection) between the bladder and either the vagina or the intestine, allowing air to enter the urinary system. Obstetric fistula, a complication of childbirth, can result in uncontrolled passage of urine into the vagina, leading to incontinence. Symptoms of urinary tract infection like dysuria or hematuria may be present, but pneumaturia is more indicative of a fistula in this context, especially when associated with a history of surgery, childbirth, or other predisposing conditions.