Why do I keep getting bacterial vaginosis?

If you have recently finished a course of treatment for Bacterial Vaginosis only to find yourself greeted with it again a couple of weeks later, then don’t worry – you’re not alone.

Although the cure rate for BV is relatively high, with a standard prescription of the antibiotic metronidazole seeing cure rates of around 80%, studies undertaken by the medical body WHO also show the recurrence rate in these cases to be 23% after 1 month, 43% after 3 months, and 58% after 12 months – meaning that well over half of women who experience BV will get it again.

There are several factors contributing to these high rates of recurrence, some of which are self-manageable, while others are beyond the individual’s control. The article below outlines some of the most common reasons for BV recurrence, helping you better manage a current or future infection.

1. Multiple Sexual Partners

While BV is not considered to be an STI due to the fact that it can be contracted without engaging in sexual intercourse, there is strong evidence to suggest that having multiple sexual partners and engaging in female-female sexual relationships increases the chance of developing BV.

This is due to a multitude of factors, including increased disturbance to the vaginal microbiome, the increased likelihood of the introduction of BV via a new partner, and during heterosexual sex, the alteration of the vagina’s bacterial flora through the more alkaline pH of semen.

In women who have sex with women (WSW), regular female partners frequently have concordant vaginal microbiota due to the regular transferral of secretions, so if one has BV the partner is more likely to also have BV. If a WSW is found to have BV, and she has a regular female partner, it would be reasonable to suggest that her partner be checked for BV and treated if positive. There is, however, no evidence that this will reduce BV recurrence.

Although this will be outlined fully at the end of this article, measures to prevent the spread of BV include reducing the number of sexual partners you might have and using condoms in heterosexual relationships. It is also recommended that individuals familiarise themselves with the symptoms of BV so that it can be identified and treated as soon as possible. Finishing a course of prescribed antibiotics is similarly paramount to prevent further spread.

2. Diminished Bacterial Immunity

Unfortunately, if you have Bacterial Vaginosis once, not only are you more likely to get it again, but you are also more at risk of acquiring subsequent STIs. Although the link between repeated bouts of BV is still not fully understood, the onset of other STIs is likely due to the decrease in the ‘bad-bacteria-fighting’ lactobacilli. During a bout of BV, abnormal anaerobic bacterial strains can increase by up to 1000%. This bacterial imbalance leaves the vagina more at risk of further infection.

Studies have found that women with BV have a 2-fold increased risk of HIV acquisition, a 1.5 to 2-fold risk of contracting chlamydia and gonorrhoea, a 9-fold risk of contracting Trichomoniasis (TV) and a 2-fold risk of acquiring HSV-2 (Genital Herpes) - compared to women without BV.

BV's recurrence can also be a result of diminished bacterial immunity resulting from a course of antibiotic treatment. As antibiotics target all bacteria to treat an infection, they can reduce the level of ‘good’ bacteria (in this case, lactobacilli) as well as the ‘bad’.

3. Having a Copper IUD

According to the NHS and the CDC, having an Intra-Uterine Device (IUD) increases your risk of bacterial vaginosis.

As Dr Hillier states in response to her study, ‘the increased risk is probably because IUDs cause heavier and longer menstrual bleeding, which is known to disturb the vaginal microbiome’ - leading to fluctuations in lactobacilli levels and the increased ability for harmful bacteria to overpower the good bacteria.

The National Institute for Health and Care Excellence (NICE) itself suggests that for those experiencing repeated bouts of BV while fitted with a Copper IUD, removing the device and considering a different mode of contraception may be the most beneficial option. However, as with any change in contraceptive method, if you are considering this option, you are advised to seek the advice of your GP beforehand to discuss in detail alternative modes of birth control. For anyone who does go ahead with removal, it is integral to continue the use of condoms to prevent the spread of other STIs and any unwanted pregnancies.

In short, there are several factors that can cause recurrent BV infections. Once you identify what triggers it, you can take precautionary steps to minimise your risk of experiencing another bout of bacterial vaginosis. For further advice on how you can prevent bacterial vaginosis, speak to your doctor or gynaecologist. There's also a wealth of knowledge readily available from the NHS website, which details common causes of bacterial vaginosis and what you can do to reduce your risk.