How the combined pill can cause recurrent thrush
Thrush, a condition with which many will be very well acquainted with, is a common term for the itchy white curd-like vaginal discharge that commonly affects women of reproductive age. The scratching and inflammation can cause irritation, cuts, and pain when peeing or having sex. The condition is caused by an overgrowth of a yeast (fungus) called Candida albicans, which explains the clinical name for thrush: vulvovaginal candidiasis.
Candida is part of the usual flora of mucous membranes in your body such as the mouth, gut, and vagina — in other words, it’s always there. And it’s not the only one. Lactobacilli are the predominant colonising bacterial organism, though you can also find half a dozen other types of bacteria. They maintain the pH of the vagina at less than 4.5. To put this into context, lemons have a pH of about 2. This acidic environment protects you from being infected by an overgrowth of organisms you don’t like, of which candida is one.
Three quarters of women will experience thrush at least once in their lifetime,1 and 10 – 20% of women will get it and not know, and their bodies will likely restore their natural balance without any treatment.2 Thrush occurs when there is a change in the bacteria of the vagina, making its pH more alkaline. You may notice you are more prone to thrush when you have your period, for instance, or after sex (blood and semen have more alkaline pH levels).
Recurrent candidiasis is diagnosed when you have ‘at least four documented episodes of symptomatic vulvovaginal candidiasis each year, with at least some relief from symptoms between episodes’.3 According to the British Association of Sexual Health guidelines on the management of vulvovaginal candidiasis published in 2007, a swab result from the lab, not a self diagnosis, should be documented on at least two occasions while you are having symptoms to aid the diagnosis of recurrent thrush. 5% of women who have thrush develop recurrent episodes.4
What does the combined pill have to do with recurrent thrush?
Having recurrent candidiasis is more a function of your body state than there being a particularly vicious fungus inside of you. It can happen if you have diabetes, if your immune system is not functioning well (perhaps you are on chemo), if you are prone to allergies, have been on antibiotics that killed off the normal bacteria living in the vagina that kept the candida in check, or (according to some studies) if you have high levels of oestrogen such as women on the combined oral contraceptive pill.
Oestrogen works on the cells of the vagina, keeping the mucosa active, and encouraging the production of glycogen. Lactobacilli use glycogen as an energy source to make their own excretion, hydrogen peroxide, and it is this hydrogen peroxide that keeps the vagina acidic, allowing the presence of good bacteria and remaining hostile to other organisms.
Hyperoestrogenic states – where you have more oestrogen than usual – occur in pregnancy, and when you are on a combined oral contraceptive pill. How the cycle is thrown off is still being studied, whether it is to do with high levels of estrogen on the glycogen production of vaginal cells, lactobacilli, or candida is still debatable. But it is accepted that changes in your natural hormonal rhythm may slightly predispose you to a change in your vaginal pH and make you susceptible to thrush.5 This explains why women in the menopause are less likely to develop vaginal candidiasis – because they are in a hypo-oestrogenic state (below normal levels of oestrogen in the body).
Can I still be on the pill if I get recurrent thrush?
If you weren’t told about thrush being a side effect of the combined oral contraceptive pill — that’s because it isn’t, or at least not directly. There are many factors at play including age, sexual activity, other medical problems, diet and lifestyle as well. Ordinarily your body is able to regulate changes in the vaginal pH despite everything going on. However if you are having several episodes of painful itchy candida discharge a year and it is affecting your quality of life, then it may be worth considering changing your contraception.
Having recurrent thrush doesn’t mean that you can’t use the pill at all, just ask your GP for a brand that contains less oestrogen in it, or switch to a progesterone only form of contraception such as the depo-provera injection or the mini pill and see if it works better for you.
Be careful of home remedies to try and tackle recurrent thrush. Vaginal douching is not going to help – it will make it worse. Some people swear by yoghurt (because it contains natural lactobacilli) but this hasn’t been proven scientifically to change bacteria levels in the vagina, it probably just acts as a way to soothe inflamed mucosa and allow the area time to heal and restore its natural balance. Similarly there is no evidence that using tea tree oil (it has anti fungal properties) can help, and it may cause sensitivity.
If you are getting recurring episodes of thrush it is important to visit your GP. If you are found to have recurrent candidiasis your doctor will first give you an anti-fungal tablet and cream to eradicate the current problem, and then place you on a low regular dose of the tablet or cream for six months. Ninety per cent of women won’t have any recurrences during that time, and almost half will remain symptom free for a year. Doctors may also advise you to moisturise externally and avoid tight clothes and perfumed soaps.6 Whatever the cause of your recurrent thrush, medical intervention or lifestyle changes will often sort it out, so there is no need to worry.
Last updated October 2017
Next update due October 2019
Disclaimer: This content is designed to provide general information and is not a substitute for medical advice. Medical opinion, practice and routine may vary from country to country and may change from time to time. The author is not liable for the results of misuse or inappropriate application of the information. If you are an individual who chooses to access this information, you should not rely on the information as professional medical advice or use it to replace any relationship with your doctor or other qualified healthcare or social care professional. For medical concerns, including decisions about medications and other treatments, individuals should always consult their doctor or, in serious cases, seek immediate assistance from emergency personnel. Individuals with any type of medical condition are specifically cautioned to seek professional medical advice before beginning any sort of health treatment. Individuals with specific queries or concerns should seek appropriately qualified medical advice. Clinicians must use their own judgement when interpreting this information and deciding how best to apply it to the treatment of patients.
- Centers for Disease Control and Prevention, ‘Vulvovaginal Candidiasis’, U.S Department of Health and Human Services, 2015, [available online], https://www.cdc.gov/std/tg2015/candidiasis.htm, (accessed 17 October 2017).
- F. C. Odds, Candida and Candidosis; A review and bibliography, 2nd ed., Bailliere Tindall, London, 1988.
- J.D. Sobel et al., ‘Vulvovaginal candidiasis: epidemiologic, diagnostic, and therapeutic considerations’, American Journal of Obstetrics & Gynecology, Vol. 178, No. 2, 1998, pp. 203-211.
- D. Daniels and G. Forster, National guideline on the management of vulvovaginal candidiasis, Clinical Effectiveness Group (Association for Genitourinary Medicine and the Medical Society for the Study of Venereal Diseases), 2007, [available online] https://www.bashh.org/documents/50/50.pdf, (accessed 17 October 2017).
- G. Fischer, ‘Chronic vulvovaginal candidiasis: what we know and what we have yet to learn’, Australasian Journal of Dermatology, Vol. 53, No. 4, 2012, pp. 247-254.
- D. Daniels and G. Forster, National guideline on the management of vulvovaginal candidiasis, 2007.