So, you're experiencing a foul, fishy smelling vaginal discharge. If your discharge smells like fish, chances are you have the most common vaginal infection: bacterial vaginosis (BV). Amongst women, BV affects around 30% of them. Some cases of BV are asymptomatic; and, in such instances, it is hard to even know you have this common bacterial infection. The classic symptoms of BV include excessive, unusual vaginal discharge; and, a foul vaginal fishy smell. The discharge can carry this offensive odor as well (some women seem to get a cheesy smell instead of a fishy smell; and, for more information on this symptom of BV, you can check out: Cheese Smelling Vaginal Discharge).
One key symptom; that indicates you either do not have BV, or you have a concomitant infection; is the presence of vaginal inflammation. If you have taken antibiotics for BV in the past, it is possible that Candida has taken root in your vagina, as well. The result of a Candida and BV infection, will be vaginal inflammation along with a foul, fishy smelling vagina. Although BV is distressing, and can greatly impact quality of life, it will not typically cause inflammation of the vagina. Many women have taken regimen after regimen of antibiotics, like metronidazole, to get rid of BV; only to have it come back yet again. This isn’t unusual; researchers speculate BV recurrence rates are as high as 50 to 80% within a year of successful treatment. And, it is known that such antibiotics, can be a precursor to a vaginal yeast infection. Yeast infections usually do not have any odor to them at all—perhaps a slight yeasty or bread like smell in severe cases. For more information you can check out: Yeast Infection Smell.
If you have had a lot of sexual activity, with an assortment of partners, your foul and smelly vaginal discharge may be a result of the sexually transmitted disease (STD) trichomoniasis. The discharge from BV will likely be white, to a shade of grey, and look quite homogeneous. So, if your vaginal discharge does not have a strong cheesy or fishy smell, and it is not white or a shade of grey, and you also are seeing inflammation of the vagina; trichomoniasis could be the cause of your bad vaginal odor and discharge.
Bacterial Vaginosis Research
The first study we will examine, published in Genitourinary Medicine [68.2 (1992): 134], delineated the history and symptoms of BV quite thoroughly. The authors state that the nomenclature for BV has gone through many transitions; yet, it is commonly referred to simply as BV. Given the mild nature of this infection of the vagina, it was first considered to be “nonspecific vaginitis.” The classically agreed upon symptoms for BV, have remained generally the same, since the condition’s discovery by medical science. The most noticeable; and classic sign of BV; is increased vaginal discharge with odor, and a strong vaginal odor. The smell caused by BV is nearly always “fishy;” although, it can have a “high cheese” smell in some cases. This fishy vaginal smell, is commonly worse after sexual intercourse or menstruation. The discharge from the vagina is typically homogeneous, adheres to the vaginal wall in a thin film, and can range in color from white to a shade of grey. The authors state the condition is present in vaginas that have an elevated pH, and overgrowth of certain bacteria; most typically Gardnerella vaginallis.
According to the study, men can also develop an infection of the primary bacterial culprit behind BV: Gardnerella vaginallis. Yet, although the penis of males can become home to this bacteria; it has been difficult to prove this is a cause of initial BV or subsequent recurrent episodes of BV. Treating men with the prescription antibiotic metronidazole was not seen to reduce the recurrence of BV in women. A quote taken from the study explains this speculated relationship between infected men and women acquiring BV:
Gardner and Dukes also found that 90% of male sexual partners of women with BV were colonised with G. vaginalis suggesting that sexual transmission may occur and hence implying a causative role. Colonisation of the male urethra and semen has since been demonstrated but the association found by Gardner et al. with male sexual partners has proved difficult to reproduce. In addition treatment of the male partner with metronidazole has not decreased the recurrence rate of BV in women.
Genitourinary Medicine [68.2 (1992): 134]
Another study, published in the International Journal of Gynecology & Obstetrics [88.3 (2005): 281-285], outlines the basic signs and symptoms of BV. According to the authors, BV is the most common vaginal infection among women of reproductive age. The symptoms of BV include a foul, smelly vaginal discharge; and, in about half of the women who have BV, it can cause vaginal irritation. BV does not cause vaginal inflammation. So, if you have a smelly, foul vaginal discharge, this is the hallmark symptom of BV. In a clinical study, the absence of a bad fishy smellm and lack of excess vaginal discharge, were criteria for being cured of BV. After you get treated for BV, these symptoms should disappear.
The authors state that the cause of BV remains unknown; however, it happens when certain bacteria, primarily the anaerobic Gardnerella vaginalis, proliferate with a corresponding reduction of lactic acid producing bacteria. In women who visited clinics for sexually transmitted diseases, about 35% of them had BV. About 15 to 20% of pregnant women will contract BV; and, amongst women going to gynecologic clinics, 5 to 15% of them will be suffering from BV.
The Source of the Odor
The next study we will investigate, gives a solid explanation as to why BV causes a foul rotten fish odor. The study was published in APMIS [113.7?8 (2005): 513-516]. According to the study’s authors, trimethylamine (TMA) is the chemical causes the vaginal fishy smell. Human urine and fish muscle contain the non-volatile version of this chemical: trimethylamine oxide (TMAO) (Bystedt, et al.; 1959). When a fish dies, the bacteria in them, decompose the trimethylamine oxide into the odorous trimethylamine. When a woman has BV, the unwelcome bacteria in her vagina also reduce the trimethylamine oxide into the highly odorous trimethylamine. Hence, the vagina, and the discharge from it, exhibit a classic fishy smell.
Surprisingly, the study may reveal that eating fish can increase the fishy odor from urine and the vagina if you currently have BV. Although this postulation was not examined by the study, the research did state that by eating fish, you will have more TMAO in your body and vaginal fluid. Healthy young adults produce about 1 mg of TMA and 40 mg of TMAO daily; and, these levels can be drastically influenced by diet. When marine fish are included in the diet, several hundred mg of TMAO can be excreted by the body. Some individuals may not properly oxidize TMA; and, thus have less TMAO and more TMA in their vaginal secretions, urine, breath, and sweat—as a result of eating marine fish. The researchers found, on average, almost three times as much TMA in women with BV than women without BV. The study deduces that higher levels of TMA can therefore be a result of the bacteria causing BV reducing TMAO to TMA, a diet high in marine fish, and a possible rare physiological problem where the body cannot properly oxidize TMA. So, if you have BV, it is reasonable to assume eating fish can aggravate the foul vaginal smell.
Bacterial Vaginosis Recurrence
Another study also discusses recurrent BV and the prevalence of BV amongst women. The study was published in The Journal of Family Practice [60.2 (2011): 91]. According to the authors, BV is the most frequent cause of vaginal discharge; being responsible for up to 40 to 50% of clinical cases. Many medical professionals even state BV recurrence can be as high as 80% within a year after treatment. Among women aged 14 to 49 in the United States, BV currently affects about 30% of this population (asymptomatic cases included in this figure). The authors relate, that even with the use of the prescription drug metronidazole, recurrence frequently happens. According to an additional study, cited by the authors, there is up to a 50% chance a woman will redevelop BV within a year after successful treatment.
The authors also relate a study done on 120 Chinese women who had a history of BV (having two or more episodes in the previous year), but did not currently have it at the moment. The study found that women who used a probiotic pill were around half as likely, at various checkpoints in the future, to have BV—as compared to women who took a placebo alone. This shows some solid evidence that probiotic use can help stymie BV; and, help keep it from coming back.
Since the rate of BV recurrence can be quite high; a method to help suppress BV more effectively was investigated in a study published in the International Journal of Gynecology & Obstetrics [108.3 (2010): 251-252]. The study took women who were suffering from recurrent BV (at least 3 different episodes in a year), who had failed to recover using 400 mg of oral metronidazole twice daily for 7 days, and divided them into two groups. The first group used a 0.75% metronidazole gel alone after menstruation; and, the second group used the metronidazole gel, plus they took a probiotic pill twice daily for three months. The study found that women who took a probiotic, in addition to using a vaginal metronidazole cream, had more success in keeping BV from recurring. The study used the Amsel criteria to diagnose BV. The following chart was taken from the study and illustrates the results of the experiment:
Trichomoniasis: Another Cause of Vaginal Odor
According to the 2014 edition of The Gale Encyclopedia of Alternative Medicine, trichomoniasis can also cause unusual vaginal odor and discharge. Like yeast infections, the use of antibiotics can increase a woman’s likelihood for contracting the protozoan that causes trichomoniasis. The text states, that the symptoms of trichomoniasis in women, include the following:
- A foul, smelly vaginal odor.
- Profuse, yellow, frothy vaginal discharge.
- Intense itching of the vaginal area.
- Inflammation and irritation of the labia, vagina, or cervix.
- Pain during urination (dysuria).
- Pain during sexual intercourse (dyspareunia).
- Women may sometimes have lower abdominal pain.
So, if you have a yellow or green vaginal discharge, you have vaginal inflammation, and do not have a “cheesy” or “fishy” vaginal odor, you may have trichomoniasis instead. But, since trichomoniasis is an STD, you can probably rule such a malady out completely, if you haven’t had unusual sexual activity. Also, BV can occur along with other vaginal problems, so if you have a classic BV associated vaginal smell and vaginal inflammation (or another classic symptom of Candidiasis or trichomoniasis), you probably have more than one vaginal infection!
The Big 3 Vaginal Infections
Yeast infections, BV, and trichomoniasis are three massively widespread vaginal infections. If you have a strange odor, and none of the other symptoms of vaginal Candidiasis, you can probably rule out completely that you have this infection. But, again, BV and trichomoniasis can resemble each other to some degree—due to both causing fishy, foul vaginal odor.
In a study published in The Female Patient [22 (1997): 39-56], the multiple medical researchers involved, stated millions of American women received prescriptions for some form of vaginitis (vaginitis is any type of vaginal infection). Of the women who will come down with some vaginal infection, BV is the most prevalent; accounting for about 45% of all vaginitis cases. Yeast infections came in second; causing about 40% of all vaginal infections. Thus, trichomoniasis isn’t as widespread as the other two primary vaginal enemies; and, sexual transmission is required for this malady’s acquisition. The following chart, was taken from the study, and shows you how to differentiate between these infections. Vaginal odor (as noted by the “amine odor”; remember trimethylAMINE), vaginal pH, discharge, and chief complaints women have with these conditions, are delineated in the chart. Note the discharge color difference between BV and trichomoniasis; this may be essential to helping you rule out trichomoniasis.
- http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1194827/ — Easmon, C. S., P. E. Hay, and C. A. Ison. "Bacterial vaginosis: a diagnostic approach." Genitourinary medicine 68.2 (1992): 134. PubMed PDF
- http://dx.doi.org/10.1016/j.ijgo.2004.11.028 — Núñez, J. T., and G. Gómez. "Low-dose secnidazole in the treatment of bacterial vaginosis." International Journal of Gynecology & Obstetrics 88.3 (2005): 281-285. PubMed
- http://dx.doi.org/10.1111/j.1600-0463.2005.apm_175.x — Wolrath, Helen, et al. "Trimethylamine and trimethylamine oxide levels in normal women and women with bacterial vaginosis reflect a local metabolism in vaginal secretion as compared to urine." Apmis 113.7?8 (2005): 513-516. PubMed
- http://dx.doi.org/10.1002/jsfa.2740100601 — Bystedt, J., L. Swenne, and H. W. Aas. "Determination of trimethylamine oxide in fish muscle." Journal of the Science of Food and Agriculture 10.6 (1959): 301-304.
- http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3183959/ — Jones, Kohar, and Bernard Ewigman. "Help for recurrent bacterial vaginosis." The Journal of family practice 60.2 (2011): 91.
- http://dx.doi.org/10.1016/j.ijgo.2009.09.029 — Thulkar, Jyoti, Alka Kriplani, and Nutan Agarwal. "Probiotic and metronidazole treatment for recurrent bacterial vaginosis." International Journal of Gynecology & Obstetrics 108.3 (2010): 251-252. PubMed
- Google Books — The Gale Encyclopedia of Alternative Medicine Ed. Laurie J. Fundukian. Vol. 4. 4th ed. Farmington Hills, MI: Gale, 2014. p2433-2435. COPYRIGHT 2014 Gale, Cengage Learning
- https://www.researchgate.net/publication/242115516 — Young, Ronald L. "Treatment considerations in vulvovaginal candidiasis." The Female Patient 22 (1997): 39-56.PDF Available Here