The pH ot vagina in adults is 1

4.5 - 5.5 The pH of vagina in an adult woman is 4 - 5.5 with an average of 4 5 The pH of vagina varies with age Age Vaglnal pH - In a newborn infantdeg Between 4.5 - 7deg - 6 weeks old child deg 7deg - Pubeydeg Changes from alkaline to acidicdeg - Reproductive age groupdeg 4S 5.5deg - Pregnancydeg 3.5 - 4.5deg -- LoLL'4 - Late post menopausaldeg 6 - 8deg pH of vagina also varies along its length, being highest in the upper pa because of admixture of alkaline cervical mucus. The acidity of vagina is because of the action of doderlein's bacilli (lactobacilli) a normal inhabitant of vagina which acts on the glycogen contained in the vaginal cells to produce lactic acid. Vagina is lined by squamous epithelium in adults and by transitional epithelium in newborn.deg No glands open in vagina.deg The squamous cells of vagina and cervix stain deep brown in colour after being painted with iodine solution, owing to the presence of glycogen in healthy cells (positive schiller test).deg