Evaluation of vaginal discharge

Vaginal discharge is a common symptom seen by clinicians. It may be physiologic or pathologic.

Physiologic vaginal discharge

Normal vaginal discharge in a reproductive-aged woman, also called physiologic discharge, usually consists of 1-4 mL per 24 hours. It is typically transparent, odorless (but can also be slightly malodorous), mucousy, and white-to-yellowish.

The character of physiologic discharge can vary over the menstrual cycle and in the different reproductive stages. For instance, it becomes more noticeable with higher estrogen states (e.g., during pregnancy, when using estrogen-progestin contraceptives, or at ovulation). Lactobacilli in the normal vaginal flora maintain vaginal acidity by producing hydrogen peroxide and lactic acid. The acidic pH of the vagina in reproductive women (4.0-4.5) creates a hostile environment for pathogens. In premenarchal and postmenopausal women with low estrogen states, vaginal pH may be 4.7 or more.

Epidemiology

Vulvovaginal symptoms are prevalent in both premenopausal and postmenopausal women.[1]Watson LJ, James KE, Hatoum Moeller IJ, et al. Vulvovaginal discomfort is common in both premenopausal and postmenopausal women. J Low Genit Tract Dis. 2019 Apr;23(2):164-9. http://www.ncbi.nlm.nih.gov/pubmed/30741753?tool=bestpractice.com ​ However, the true prevalence of pathologic vaginal discharge is uncertain because vaginitis, which encompasses the symptom vaginal discharge, is often asymptomatic, self-diagnosed, and self-treated.[2]Foxman B, Marsh JV, Gillespie B, et al. Frequency and response to vaginal symptoms among white and African American women: Results of a random digit dialing survey. J Womens Health. 1998 Nov;7(9):1167-74. http://www.ncbi.nlm.nih.gov/pubmed/9861594?tool=bestpractice.com

Abnormal vaginal discharge was reported by 14.5% of 3000 women (ages 18-50 years) who were randomly sampled from a population in Goa, India, in one community-based survey.[3]Patel V, Pednekar S, Weiss H, et al. Why do women complain of vaginal discharge? A population survey of infectious and pyschosocial risk factors in a South Asian community. Int J Epidemiol. 2005 Aug;34(4):853-62. https://academic.oup.com/ije/article/34/4/853/692864?login=false http://www.ncbi.nlm.nih.gov/pubmed/15833795?tool=bestpractice.com ​ Within one US community-practice setting, abnormal vaginal discharge was reported by 68% of women presenting with symptoms of vaginitis.[4]Hillier SL, Austin M, Macio I, et al. Diagnosis and treatment of vaginal discharge syndromes in community practice settings. Clin Infect Dis. 2021 May 4;72(9):1538-43. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8248297 http://www.ncbi.nlm.nih.gov/pubmed/32350529?tool=bestpractice.com

Most women will experience more vaginal discharge during pregnancy.[5]National Institute for Health and Care Excellence (UK). Antenatal care. Aug 2021 [internet publication]. https://www.nice.org.uk/guidance/ng201 ​ The prevalence of pathologic vaginal discharge during pregnancy has been reported to be 40% to 50%.[6]da Fonseca TM, Cesar JA, Mendoza-Sassi RA, et al. Pathological vaginal discharge among pregnant women: pattern of occurrence and association in a population-based survey. Obstet Gynecol Int. 2013;2013:590416. https://www.hindawi.com/journals/ogi/2013/590416 http://www.ncbi.nlm.nih.gov/pubmed/23843798?tool=bestpractice.com [7]Prasad D, Parween S, Kumari K, et al. Prevalence, etiology, and associated symptoms of vaginal discharge during pregnancy in women seen in a tertiary care hospital in Bihar. Cureus. 2021 Jan 14;13(1):e12700. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7883588 http://www.ncbi.nlm.nih.gov/pubmed/33614308?tool=bestpractice.com [8]Cesar JA, Mendoza-Sassi RA, González-Chica DA, et al. Prevalence of self-reported vaginal discharge and associated factors in pregnant women [in Portuguese]. Cad Saude Publica. 2009 Dec;25(12):2705-14. https://www.scielo.br/j/csp/a/WZhWNVpTHL9fMv9QdjGnp7R/?lang=pt http://www.ncbi.nlm.nih.gov/pubmed/20191161?tool=bestpractice.com ​​​​