The Microbiome and Birth Control
The vaginal microbiome is becoming increasingly popular nowadays, and so I wanted to explore the relationship between it and hormonal birth control. I wanted to investigate if being on a form of hormonal contraception increased the risk of getting a vaginal infection. All the studies that I looked at ranged between 2014 and 2018, and looked at a variety of birth control options including combined oral contraceptive pills, progestin-only pills, the depo shot, copper IUD, and mirena IUS.
Types of Birth Control
Combined Oral Contraceptives
In one study, there were more hydrogen peroxide producing lactobacilli, and less BV-associated bacteria compared to condom users.
Women taking progestin-only pills, in one study, seemed to readily develop aerobic vaginitis (aka. abnormal flora) and vaginal atrophy (aka. thinning, drying, and inflammation of the vaginal walls). However, compared to Mirena users, women taking Mirena has a less likelihood of getting a candida infection. In fact, another study showed that women with a recurrence of vulvovaginal candidiasis should take progestin-only pills instead of intrauterine contraception.
Depo Provera Shot
One study showed that a proportion of women with the Depo provera shot, had more Lactobacillus-dominated vagitypes than compared to condom users.
According to a few studies, there was an asymptomatic prevalence of bacterial vaginosis in women with the copper IUD. One study looked at the time in which women began using this form of contraception, and BV prevalence continued to increase 6 months after the IUD was inserted. Moreover, another study showed that in women with the copper IUD, there was a trend towards BV, abnormal flora, increased pH (remember vaginal pH is about 3.8-4.5) and candida infections.
There are mixed accounts of how Mirena affects the vaginal microbiome. In one study compared to the combined contraceptive pill, there were greater amounts of BV-associated bacteria in women with the Mirena device. This study indicated that Mirena may have a negative effect on the vaginal microbiome. With respect to Candida, women using Mirena has a higher risk of Candida compared to women not using any form of contraception.
Two other studies said that compared to copper IUD users, long-term Mirena users had a lower risk of abnormal microflora, and that the vaginal microbiome changes very little in response to Mirena.
Lastly a final study found a found a temporary worsening in lactobacilli and increased rates of BV after 3 months of Mirena use (compared to pre-insertion). However, after 1 and 5 years, the flora changes were reversed. Ultimately, there was a complete restoration to pre-insertion levels. However, candida increased significantly after long-term Mirena (when compared to pre-insertion).
Depending on the type of birth control you’re using, it’s important to be aware of any potential effects it may have on your vaginal microbiome. Moreover, if you find yourself getting constant infections – one of the causes may be the type of birth control you’re using! In that case, it may be best to start taking a vaginal probiotic and immune support, all under the supervision of a Naturopathic Doctor.
Brooks J, Edwards D, Blithe D et al. Effects of combined oral contraceptives, depot medroxyprogesterone acetate and the levonorgestrel-releasing intrauterine system on the vaginal microbiome. Contraception. 2017;95(4):405-413. doi:10.1016/j.contraception.2016.11.006.
Achilles S, Austin M, Meyn L, Mhlanga F, Chirenje Z, Hillier S. Impact of contraceptive initiation on vaginal microbiota. Am J Obstet Gynecol. 2018. doi:10.1016/j.ajog.2018.02.017.
Donders G, Bellen G, Janssens D, Van Bulck B, Hinoul P, Verguts J. Influence of contraceptive choice on vaginal bacterial and fungal microflora. European Journal of Clinical Microbiology & Infectious Diseases. 2017;36(1):43-48. doi:10.1007/s10096-016-2768-8.
Jacobson J, Turok D, Dermish A, Nygaard I, Settles M. Vaginal microbiome changes with levonorgestrel intrauterine system placement. Contraception. 2014;90(2):130-135. doi:10.1016/j.contraception.2014.04.006.
Donders G, Bellen G, Ruban K, Van Bulck B. Short- and long-term influence of the levonorgestrel-releasing intrauterine system (Mirena®) on vaginal microbiota and Candida. J Med Microbiol. 2018;67(3):308-313. doi:10.1099/jmm.0.000657.