Women’s health specialist Louise Newson continues her feature on the management of vulvovaginal infections in general practice.

Dr Louise R Newson GP, Shirley Medical Practice, Solihull, West Midlands



Mrs TH is a 34 year old lady who comes to see her GP as she has a troublesome vaginal discharge which is often very malodorous and she has become very embarrassed about it. She has no vaginal itching or soreness and is otherwise well. She had a copper-bearing intrauterine device inserted a year ago, following the birth of her second child and reports that her symptoms have been intermittent since this time. She has been married for 10 years and has had the same sexual partner for the past 13 years. She is not pregnant and has never had a blood-stained discharge. She has been treating herself with over the counter treatments for thrush, but these have not helped in any way.


Although the most common causes of altered vaginal discharge are physiological, bacterial vaginosis (BV) and candida, sexually transmitted infections (STIs) and non-infective causes must be considered, when appropriate. 

Bacterial vaginosis

Bacterial vaginosis (BV) is thought to be the commonest cause of abnormal vaginal discharge in women of childbearing age. 1 BV is extremely common, affecting 10% to 30% of women, and it recurs in 15% to 30% within three months after treatment. 2 Even though BV is so common, it remains frequently underdiagnosed, and few women in the UK actually know about it.3 BV is twice as prevalent as vaginal candidiasis and affects a third of women in the UK at least once in their lifetime. 

BV may co-exist with other causes of abnormal discharge, such as candidiasis, trichomoniasis and cervicitis. It often presents and then can remit spontaneously in both sexually active and sexually inactive women. It is therefore not a sexually transmitted infection. 

BV is caused by an overgrowth of predominantly anaerobic organisms (e.g. Gardnerella vaginalis , Prevotella spp ., Mycoplasma hominis ) in the vagina. These replace lactobacilli and the pH increases from <4.5 to as high as 7.0. Gardnerella vaginalis is commonly found in women with BV, but the presence of gardnerella alone is insufficient to constitute a diagnosis of BV. Other organisms associated with BV include Prevotella spp ., Mycoplasma hominis and Mobiluncus spp.


BV is associated with starting intercourse at an early age and having a higher number of sexual partners in a lifetime. Women who have an intrauterine device (IUD) seem to be at increased risk for bacterial vaginosis. 4
Other risk factors for BV include:

  • Vaginal douching  
  • Receptive cunnilingus  
  • Black race
  • Recent change of sexual partner  
  • Smoking  
  • Presence of an STI, e.g. chlamydia or herpes

The progestogen-only implant and injectable may be associated with a decreased risk of BV. 5 Taking the combined oral contraceptive pill, using condoms and having a circumcised male partner also appear to protect from BV infections. 6


Making a diagnosis

A detailed history is very important and should include sexual history, contraceptive use, treatments tried (including OTC) and responses, and if there have been any new allergens. 1 Making a diagnosis of BV in primary care is often very difficult. 6

Symptoms of BV

Most women have a natural vaginal discharge, which is usually odourless and clear or whitish in colour. The amount of this discharge is different for each woman and often varies throughout the month. The discharge in women with BV is normally thin whitish/grey and usually has an offensive fishy odour. There is typically no itching and usually no other symptoms. Some women with BV have no symptoms at all.

Signs of BV 

Signs of BV may include:

  • Presence of discharge coating the vagina and the vestibule  
  • Absence of vulval inflammation

Differential diagnoses 


These may include other vaginal infections, such as candida, chlamydia and gonorrhea. Other differential diagnoses include dermatitis, allergic reactions and atrophic vaginitis in peri- and post-menopausal women.


BV is often very difficult to diagnose in primary care, and the diagnosis is often based on the presence of a malodorous discharge with a raised pH.

It is standard clinical practice to offer an examination to women presenting with genital symptoms. However, if the history indicates BV, the risk of a sexually transmitted infection is low and there are no symptoms indicative of upper genital tract infection, then treatment for BV may be given without examination (i.e. syndromic management – see below). 8 In these cases, all women should be advised to return for an examination if their symptoms persist or recur. 




Syndromic management, a frequently used approach in genitourinary medicine, is based on the identification of consistent groups of symptoms and easily recognised signs, and the provision of treatment that will deal with the majority or most serious organisms responsible for producing a syndrome.


Women who are examined should have a vaginal pH measurement using narrow-range pH paper (pH 4–7). Secretions should be collected from the lateral sides of the vaginal wall using a loop or swab. Although vaginal pH testing can be used to assess the likelihood of candida (pH≤4.5) or of BV or TV (pH >4.5), it cannot distinguish between BV and trichomonal infection. 8 The normal vaginal pH is 3.5-4.5. 

Most GU laboratories make a diagnosis of BV based on one of two approaches described in Figure 1.

Management of Vulvovaginal infections in primary care - Part 2 Fig 1

Although high vaginal swabs (HVSs) are often used to diagnose causes of vaginal discharge, they are of limited value, and reporting of commensal bacteria can cause anxiety and lead to overtreatment. The isolation of Gardnerella vaginalis on HVS culture should not be used to diagnose BV as it is found in 30-40% of “normal” women. 6


All women with BV should be advised to avoid vaginal douching, use of shower gel and use of antiseptic agents or shampoo in the bath. These can all affect the normal vaginal flora and thereby allow BV to develop .

Treatment for BV is usually recommended for women who are symptomatic, those women who are undergoing some surgical procedures (e.g. termination of pregnancy) and for some pregnant women (e.g. those who are symptomatic). 7 If a pregnant woman is incidentally found to have BV and has no symptoms, then it is recommended that the woman’s obstetrician should be consulted to determine whether treatment is appropriate. 9 There is no evidence that opportunistic screening for (and treatment of) BV reduces risk of preterm birth. 10
The current recommended regimes are listed in Table 1

Management of Vulvovaginal infections in primary care - Part 2 Table 1

Oral metronidazole is the recommended first-line treatment for BV in the UK because it is less expensive than vaginal preparations and safer than oral and topical clindamycin, which have been associated with pseudomembranous colitis. 7 However, alternative treatments should be considered for women who experience side effects on oral metronidazole, such as metallic taste and gastrointestinal symptoms.

Note: Alcohol should be avoided for the duration of treatment with nitroimidazole drugs (e.g. metronidazole and tinidazole) and for 48 hours afterwards because of the possibility of a disulfiram-like reaction. Vaginal gels and creams may weaken condoms, so women need to be advised of this.


High initial cure rates (70–80%) are achieved with medical treatment. In the treatment of non-pregnant women with BV, clindamycin and metronidazole treatments show comparable efficacy in terms of eradication of symptoms, irrespective of dosing regimen or route of administration. 11 

Treatment of male partners has not been shown to be effective in preventing recurrence of BV in women, 12 therefore routine testing and treatment of male sexual partners is not currently recommended. However, studies have found that bacterial vaginosis is more common among women with female partners and so consideration may be given to testing and treating female partners of women with BV. 8,13

Repeat investigations following treatment is indicated only in women whose symptoms do not resolve or in those who are pregnant, in whom it is recommended to repeat a screen one month later to ensure eradication. 

There is no good evidence to support the use of non- antibiotic based treatment with probiotic lactobacilli or lactic acid preparations for BV, and they are therefore not currently recommended. 14

Management of complicated bacterial vaginosis

BV in women who are pregnant or breast feeding

The National Institute for Health and Care Excellence (NICE) does not recommend routine screening for BV, because the evidence suggests that identification and treatment of asymptomatic BV does not lower the risk for pre-term birth and other adverse reproductive outcomes. 15 Current guidelines support screening only for women with a previous preterm birth or second- trimester miscarriage, as treatment of BV before 20 weeks’ gestation and treatment of women with a previous preterm birth may reduce adverse pregnancy outcomes. 7 If BV is identified as a cause of vaginal discharge or as an incidental finding during pregnancy, it should be treated. 

However, the British HIV Association recommends screening for BV in pregnant women who are infected with HIV because there is an increased risk of mother- to-child transmission of HIV-1 in the presence of BV. 16

Women with BV who are pregnant may use metronidazole 400mg twice daily for 5–7 days, or intravaginal therapies. A 2g stat dose of metronidazole is not recommended in pregnancy or breastfeeding women. Intravaginal treatment is preferable to oral antibiotics for women who are breastfeeding, as metronidazole and clindamycin enter the breast milk .

Recurrent BV 

There is no specifically agreed definition of recurrent BV. Despite high initial cure rates, recurrence of BV is high.17 One study found that the risk of BV recurrence was increased with the same pre- and post-treatment sexual partner and inconsistent condom use, and the risk halved with use of oestrogen-containing contraceptives.17

Women with recurrent BV need to be advised that this is very difficult to manage and it is important that they have realistic expectations regarding success of treatment. Advice regarding stopping smoking and avoiding douching should be reiterated. 

Episodic, anticipatory, pulse or suppressive treatment for 4–6 months should be considered. Examples include:6

  • Oral metronidazole 400 mg po bd for 3/7 at start and end of menstruation  
  • Oral metronidazole 2 g po stat once a month  
  • Oral metronidazole 0.75% vaginal gel pv twice a week for 16 weeks 

Women using acidifying gels for recurrent BV can be advised to use them alternate evenings for one month or longer if required. The current evidence regarding the effectiveness of acidifying agents is uncertain, as the studies so far have all been small. 6


Women with a copper-bearing intrauterine device who experience recurrent BV may wish to consider switching to an alternative method of contraception. 

If symptoms recur, the history should be reviewed and other causes considered. Referral to a specialist clinic (e.g. GUM, vulval clinic) should also be considered. 

Complications BV is thought to lead to an increased risk of contracting sexually transmitted infections, including HIV, gonorrhoea and chlamydia. 7 The mechanism behind this is not clear.
BV during pregnancy is associated with adverse events, including late miscarriage, preterm labour, premature rupture of membranes, low birth weight and postpartum endometritis.18

Pregnant women with BV are twice as likely to have a premature birth as other women. It is thought that BV is responsible for one in three of all premature births in the UK, and pregnant women with BV are six times more likely to have a miscarriage than other women.7

BV is associated with post-operative endometritis and also pelvic inflammatory disease following a surgical termination of pregnancy. Although the reasons for this link are unclear, women are usually screened for BV prior to this operation. 6

Trichomonas vaginalis (TV) 

TV is a flagellated protozoan, which is a sexually transmitted infection. The symptoms of TV can be confused with BV and TV is still underdiagnosed and therefore undertreated. Trichomonas vaginalis is the most common curable sexually transmitted infection worldwide. 19

Symptoms of TV

The discharge associated with TV varies from being very scanty to very profuse. Around half of women with TV have no symptoms.6 The discharge, when present, is usually offensive smelling and most women complain of a vulval itch and soreness. They may also have symptoms of dysuria and lower abdominal pain.

Signs of TV

A frothy yellowish discharge may be present. There may be signs of local inflammation with vulvitis and vaginitis. Cervicitis may be present, which leads to the cervix having the appearance of the surface of a strawberry – sometimes referred to a “strawberry cervix”. Around 15% of women will have no abnormal signs (other than a raised pH).

Diagnosis of TV 

If TV is suspected in a patient, then it is recommended that she is referred to the local GU clinic for appropriate testing, treatment and also contact tracing. 6 Patients with TV also need testing for other STIs. 

If TV is suspected an HVS can be taken from the posterior fornix, but sensitivity may be low because motility reduces with transit time. Therefore, referral to GUM is recommended for confirmation by wet microscopy +/– culture, and also for partner notification. Laboratories may not routinely perform wet microscopy or TV culture, so suspected TV should be mentioned on the laboratory request form. 

Complications of TV include pre-term delivery and low birth weight. 

Treatment of TV 

Although a single oral dose can achieve cure, side effects may be more frequent when compared with a longer course of treatment. Systemic treatments are far more effective than topical treatments and include:6

  • Oral metronidazole 2g po stat (avoid in pregnancy/ breastfeeding)  
  • Oral metronidazole 400mg to 500mg bd for 5-7 days 

Treatment of partners is also recommended, regardless of their results. 9 Test of cure is only recommended if symptoms persist or recur.



As Mrs TH was at low risk of a STI and had a history to suggest bacterial vaginosis, she was given syndromic treatment based on her history, namely oral metronidazole 400mg bd for seven days. She returned to see her GP one month later for a follow up appointment and was delighted that all her symptoms had disappeared. She was advised that if her symptoms return she may consider having the IUD removed and taking the combined oral contraceptive pill as an alternative form of contraception.



1 The incidence of BV is high, affecting up to 30% of women, with high recurrence rates
2 BV is caused by a variety of organisms that replace the commensal lactobacilli
3 Key risk factors include sexual activity at an early age, high number of partners and IUD
4 Diagnosis is challenging; symptoms vary but usually include white or grey, malodorous discharge
5 Vaginal pH will be raised in women with BV, but this does not distinguish BV from trichomonal infection
6 In certain cases, treatment of BV may be undertaken without examination High initial cure rates are achieved with both topical and oral anti-infectives
7 BV in pregnant women should always be treated, usually with topical preparations 8 Women should be made aware of the high risk of recurrence and advised about preventive measures
9 Women with suspected TV should be referred to the GUM clinic



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