Dear Ms Priscila A few more questions - how old is your baby. Is the bulge visible only when she cries/ strains or is it seen always. Does it have a bluish discoloration. I have an idea what it is, but would like the above questions answered. The possibilities are (i) Imperforate vagina with intact hymen - leads to hydrometrocolpos which can have this bulge in the vagina (ii) Ureterocele - ectopic opening of the ureter (pipe draining urine) which in some girls may be placed abnormally in the vaginal wall especially in the wall closer to the front than the back. Both these are very easily diagnosed with ultrasound scans and easily treated as well. Do get back with the answers. Thanks.