Abnormal vagina morphology Imperforate hymen Imperformate hymen is caused by a failure of the hymen to perforate during fetal development. It is most often diagnosed in adolescent girls when menstrual blood accumulates in the vagina and sometimes also in the uterus. It can be treated by surgical incision of the hymen. SNOMEDCT_US:65937002 A congenital disorder where the hymen (a membrane that surrounds or partially covers the external vaginal opening) does not have an opening and completely obstructs the vagina. UMLS:C0152436