Thanks for the query.
I understand your concern.
The possible causes of swelling of left side of vagina are vaginal infection, allergy to inner wear, dilated blood vessels in the walls of vagina due to increased pressure over vessels by pregnant uterus, cysts along vaginal wall like Gartner's cyst.
By clinical examination, checking the blood pressure and ultrasound the exact cause of the problem can be identified.
So, please do consult your doctor and get evaluated.
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